anunoy@chromium.org chrome-counter-abuse-alerts@google.com The number of extensions that were blocklisted when already installed, grouped by Extension::Location. Logged when ExtensionService blockists and unloads an installed extension. Warning: this histogram was expired from 2024-10-23 to 2025-11-13; data may be missing. anunoy@chromium.org chrome-counter-abuse-alerts@google.com The number of extensions that have been blocked from installing grouped by Extension::Location. Logged when ExtensionService refuses to install a blocklisted extension. anunoy@chromium.org chrome-counter-abuse-alerts@google.com The number of extensions that have been silently installed in a blocklisted state, grouped by Extension::Location. Logged when ExtensionService installs a blocklisted extension without blocking it (ExtensionBlacklist.BlockCRX would be logged otherwise). Typically this will be when a user has a blocklisted extension synced. Warning: this histogram was expired from 2024-10-23 to 2025-11-13; data may be missing. anunoy@chromium.org chrome-counter-abuse-alerts@google.com The number of extensions that were unblocklisted when installed, grouped by Extension::Location. Logged when ExtensionService unblocklists and loads a blocklisted extension. Warning: this histogram was expired from 2024-07-28 to 2025-11-13; data may be missing. lazyboy@chromium.org extensions-core@chromium.org The time taken to create the computed_hashes.json file for an extension. This happens once for each extension after we get signed values of the expected root node of a tree hashes for each file from the webstore; we then compute the individual block level hashes of the actual files and cache them in computed_hashes.json (assuming we don't detect any mismatches). ydago@chromium.org extensions-core@chromium.org Records whether an extension must remain disabled. Recorded when ExtensionService checks if an extension must remain disabled. ydago@chromium.org extensions-core@chromium.org Records the result of checking if an extension is allowed to be installed. Recorded when ExtensionService checks if an extension is allowed. ydago@chromium.org extensions-core@chromium.org Records the result of fetching the extension install policy. Recorded when ExtensionService checks if a user can install an extension. ydago@chromium.org extensions-core@chromium.org Records the time it takes to fetch the extension install policy. Recorded when ExtensionService checks if a user can install an extension. ydago@chromium.org extensions-core@chromium.org Records whether a user may load an extension. Recorded when ExtensionService checks if a user may load an extension. rdevlin.cronin@chromium.org bershanskyi@gmail.com extensions-core@chromium.org The length (in bytes) of the badge text string provided to action.setBadgeText(). Recorded each time an extension calls the method successfully. rdevlin.cronin@chromium.org bershanskyi@gmail.com extensions-core@chromium.org The length (in bytes) of the title string provided to action.setTitle(). Recorded each time an extension calls the method successfully. rdevlin.cronin@chromium.org bershanskyi@gmail.com extensions-core@chromium.org The length of the longest alarm name (in characters) an extension has set. It is emitted every time an extension is loaded (during user profile load). It is not emitted for extensions that do not have any saved alarms on extension load. benwells@chromium.org dominickn@chromium.org tapted@chromium.org The number of times v1 apps are launched grouped by extension_misc::AppLaunchBuckets. See also Apps.AppLaunch for v2 apps. Note this was changed in 2023-02 to no longer count web app launches. benwells@chromium.org tapted@chromium.org The number of apps loaded on profile open time grouped by Extension::Location. rdevlin.cronin@chromium.org extensions-core@chromium.org emromero@microsoft.com Number of scripts to be injected at document start that were eligible for background compilation. Emitted when `extensions_features::kExtensionsBackgroundCompilation` is enabled, the navigation is ready to commit, and the scripts have started streaming to v8 for compilation. rdevlin.cronin@chromium.org extensions-core@chromium.org emromero@microsoft.com Number of scripts injected at document start that were eligible for background compilation, as a percentage of all scripts injected at document start. Emitted at the same time as Extensions.BackgroundCompileInjectedScripts.EligibleScriptsCount. rdevlin.cronin@chromium.org extensions-core@chromium.org emromero@microsoft.com Time taken to compile an extension JS script injected at document start that was compiled in a background thread. Emitted asynchronously on the main thread immediately after the background thread completes script compilation. The background worker calls Run(), then posts EmitCompilationHistograms() back to the main thread via PostNonNestableTask(). rdevlin.cronin@chromium.org extensions-core@chromium.org emromero@microsoft.com Number of characters of an extension JS script injected at document start that was compiled in a background thread. Emitted simultaneously with ScriptCompilationTime{State}. fdoray@chromium.org catan-team@chromium.org Recorded when a background host is created for an extension. The value indicates for which extension the host was created. The breakdown of extensions that make up the "Other extension" bucket can be derived from the LoadCountsPerTopLevelDocument UKM event. To compare UKM event counts with UMA sample counts, use this formula: count of UKM events for a given extension * count of samples in the "Other extension" bucket of this histogram / count of UKM events for all extensions Extensions bundled with Chrome have dedicated values in this histogram because they are not synced and therefore not reported through UKM. rdevlin.cronin@chromium.org extensions-core@chromium.org The time taken for an extension's persistent background page to load its initial URL. rdevlin.cronin@chromium.org extensions-core@chromium.org The type (if any) of background page the extension has. Recorded for installed extensions on profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of times each Extension function call sends a bad message, killing the renderer. This may indicate a bug in that API's implementation on the renderer. Note a similar, aggregate metric is BadMessageTerminate_EFD which counts the number of bad messages that are sent overall. rdevlin.cronin@chromium.org extensions-core@chromium.org The reason a valid ExtensionSyncData could not be parsed from a SyncData received from sync. richche@chromium.org chrome-counter-abuse-alerts@google.com Records when a command-line extension is installed. Emitted on every profile open only for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). richche@chromium.org chrome-counter-abuse-alerts@google.com Records the default search engine, new tab page, both, or none of the overrides in a command-line extension's manifest when installed. Emitted on every profile open only for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). kelvinjiang@chromium.org extensions-core@chromium.org The size, in KB, of a content script that is loaded successfully from a file. Recorded when the content of a user script object is set. kelvinjiang@chromium.org extensions-core@chromium.org The size, in KB, of all newly loaded dynamic content scripts for one extension. Recorded when a script load containing at least one new dynamic content script finishes. kelvinjiang@chromium.org extensions-core@chromium.org The size, in KB, of all newly loaded manifest content scripts for one extension. Recorded when a script load containing at least one new manifest content script finishes. estark@chromium.org extensions-core@chromium.org An entry is emitted each time an extension sets a content setting whose primary pattern matches the Chrome extension origin. This will be used to determine if the ability to set content settings for Chrome extension origins can be deprecated. This happens on profile startup (for stored settings) and each time an extension calls chrome.contentSettings[type].set(...). erikchen@chromium.org extensions-core@chromium.org An entry is emitted each time an extension sets a content setting whose primary pattern is unique and secondary pattern is a different unique. This happens on profile startup (for stored settings) and each time an extension calls chrome.contentSettings[type].set(...). erikchen@chromium.org extensions-core@chromium.org An entry is emitted each time an extension sets a content setting whose primary pattern is unique and secondary pattern is identical to the primary pattern. This happens on profile startup (for stored settings) and each time an extension calls chrome.contentSettings[type].set(...). erikchen@chromium.org extensions-core@chromium.org An entry is emitted each time an extension sets a content setting whose primary pattern is unique and secondary pattern is a wildcard. This happens on profile startup (for stored settings) and each time an extension calls chrome.contentSettings[type].set(...). erikchen@chromium.org extensions-core@chromium.org An entry is emitted each time an extension sets a content setting whose primary pattern is a wildcard and whose secondary pattern is unique. This happens on profile startup (for stored settings) and each time an extension calls chrome.contentSettings[type].set(...). erikchen@chromium.org extensions-core@chromium.org An entry is emitted each time an extension sets a content setting whose primary and secondary pattern are both wildcard. This happens on profile startup (for stored settings) and each time an extension calls chrome.contentSettings[type].set(...). estark@chromium.org extensions-core@chromium.org An entry is emitted each time an extension sets a content setting whose secondary pattern matches the Chrome extension origin. This will be used to determine if the ability to set content settings for Chrome extension origins can be deprecated. This happens on profile startup (for stored settings) and each time an extension calls chrome.contentSettings[type].set(...). giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com extensions-core@chromium.org Whether or not computed_hashes.json file was successfully generated and written during extension installation. Recorded during installation of an extension if hashes computing was requested for this specifix extension. Hashes computing on installation is used for off-store policy-based extensions since we need them to be checked against corruption and cannot use Chrome Web Store for source of hashes. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com extensions-core@chromium.org The time taken to successfully create the computed_hashes.json file for an extension upon installation. The histogram is collected with &Extensions.ContentVerification.ComputeHashesOnInstallResult& (in case of success). giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com extensions-core@chromium.org Error info for fetching verified_contents.json. Recorded when the file wasn't available locally and we failed to fetch it from network. Note that OK may also be reported in some cases, for example, when file was successfully fetched, but is incorrect. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com extensions-core@chromium.org Whether or not fetching verified_contents.json succeeded. Recorded when the file wasn't available locally and we needed to fetch it from network. Warning: this histogram was expired from 2022-02-01 to 2022-09-22; data may be missing. rdevlin.cronin@chromium.org extensions-core@chromium.org The type of file content verification failed to verify. Emitted at the time content verification fails, once per file that failed. rdevlin.cronin@chromium.org extensions-core@chromium.org The content verification failure reason for why a {VerifiedFileType} failed. Emitted when content verification fails for a {VerifiedFileType}. rdevlin.cronin@chromium.org extensions-core@chromium.org Reports the result of a given content verification job succeeded for any extension (independent of manifest version). Emitted when the job is complete. A content verification job is started for a given extension resource request. rdevlin.cronin@chromium.org src/extensions/OWNERS Records the action taken by the user from the extension icon context menu. arichiv@google.com src/net/cookies/OWNERS Emits when a valid partitionKey argument is supplied to chrome.cookies APIs getting/editing cookies. The enum value is true when the partitonKey is 'well formatted' (identical to a SchemefulSite) and false when the partitonKey is otherwise coercible. jlulejian@chromium.org extensions-core@chromium.org The reason why an extension was detected to be corrupted. Recorded each time an extension is disabled due to corruption detection. Warning: this histogram was expired from 2022-12 to 2023-11, and 2024-011 to 2025-12; data will be missing during these timeframes. jlulejian@chromium.org extensions-core@chromium.org Logged once on profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed. This is the value of a counter that is incremented anytime we disable a corrupted extension because its content didn't match an expected content hash. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com extensions-core@chromium.org Fires when we suspect corruption in an enterprise policy forced install extension and begin the process of reinstalling it, saving reason of such suspection. Compare to CorruptPolicyExtensionResolved to judge success rate. Note that if extension was not reinstalled in the session when corruption was found, it will be detected again (possible several times, every session start will trigger a detection until the extension will be fixed), but as CORRUPTION_DETECTED_IN_PRIOR_SESSION. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com extensions-core@chromium.org managed-devices@google.com Fires when we've successfully reinstalled a corrupt enterprise policy force-installed extension, with a value indicating how long it took end-to-end to complete the reinstall (including download time). anunoy@chromium.org chrome-counter-abuse-alerts@google.com Records whether the overall extension metadata fetch from the Chrome Web Store (CWS) succeeded or not. This is recorded once for a metadata fetch (which can include multiple network requests). Metadata fetches occur periodically (default period is 24 hours). But they can also occur on-demand, for example, when new extensions are installed. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Records whether the extension metadata retrieved from the Chrome Web Store (CWS) by the latest metadata fetch is different from that currently saved. This difference can result from store metadata changing, for example an extension getting unpublished. Metadata is also changed when data for newly installed extensions is retrieved for the first time. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Records the network result for an individual network request within a metadata fetch. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Counts how many retries were needed to successfully complete an individual request within a metadata fetch. This is emitted only for a successful request. Requests are made in batches at every metadata fetch interval (default is 24 hours). anunoy@chromium.org chrome-counter-abuse-alerts@google.com Records the number of individual network requests made to retrieve metadata for all installed extensions. Each request is limited to a small number of extension ids (default is 3) so multiple requests are necessary when the number of installed extensions is greater than the per-request limit. This histogram is emitted before sending the first request in a metadata fetch. It is recorded regardless of whether the metadata fetch succeeds or fails. jlulejian@chromium.org extensions-core@chromium.org Records the operation being attempted when a chrome.storage.local (LevelDB) database error occurs. It is emitted during the execution of a storage API call from an extension. jlulejian@chromium.org extensions-core@chromium.org The result of a repair attempt on a corrupted chrome.storage.local LevelDB database. This is emitted during an open or read operation if the underlying database is found to be corrupted. jlulejian@chromium.org extensions-core@chromium.org The high-level ValueStore status of chrome.storage.local.{StorageOperation} operations on the extensions database. It is emitted during the execution of a storage API call by an extension, regardless of whether the operation succeeded or failed. dmurph@chromium.org pwnall@chromium.org The result of an open attempt to an Extensions database. {ExtensionsDatabaseOpen} richche@google.com anunoy@chromium.org How many days ago an extension was first installed. Recorded during the InstalledLoader::RecordExtensionsMetrics function. Buckets are every 91 days which approximately corresponds to a fourth of a year. richche@google.com anunoy@chromium.org How many days ago an extension was updated. Recorded during the InstalledLoader::RecordExtensionsMetrics function. Buckets are every 91 days which approximately corresponds to a fourth of a year. rdevlin.cronin@chromium.org src/extensions/OWNERS Number of calls to the declarative API extension functions. This includes the declarativeContent and declarativeWebRequest APIs. Emitted when the extension function is called. kelvinjiang@chromium.org extensions-core@chromium.org Number of times declarative content actions types are created. Emitted each time a new declarative content action type is created for an extension. kelvinjiang@chromium.org src/extensions/OWNERS Indicates whether a RulesetManager::AddRuleset() follows another call for the same extension. Recorded for every RulesetManager::AddRuleset() call. The intended behavior is that there are no such redundant calls. See crbug.com/358617943. kelvinjiang@chromium.org src/extensions/OWNERS Measures the time taken to load a single indexed ruleset in the browser process for an extension. This includes reading the indexed ruleset file and verifying it. Emitted whenever a single file-backed extension ruleset is loaded. kelvinjiang@chromium.org src/extensions/OWNERS Time taken to evaluate the action for a network request for a single extension ruleset for rules matched before the request is sent. Emitted for each network request that is visible to the extension. This is only emitted for users with high resolution clocks. kelvinjiang@chromium.org src/extensions/OWNERS Time taken to evaluate the action for a network request for a single extension ruleset for rules matched after a request's response headers have been received. Emitted for each network request that is visible to the extension. This is only emitted for users with high resolution clocks. Note: this histogram was expired from 2025-06-30 to 2025-08-28; data may be missing. kelvinjiang@chromium.org src/extensions/OWNERS Time taken to evaluate the action to take for the network request as per the Declarative Net Request API. This includes the time taken to evaluate all the extension rulesets. Emitted for non-sensitive network requests seen by the Extension System when there is at least one active extension ruleset. This is only emitted for users with high resolution clocks. Note: this histogram was expired from 2025-02-02 to 2025-03-25; data may be missing. kelvinjiang@chromium.org extensions-core@chromium.org Time taken to index and persist to disk the deserialized json rules provided by an extension manifest for the Declarative Net Request API. This is emitted whenever a packaged extension with a declarative ruleset is installed or updated. kelvinjiang@chromium.org src/extensions/OWNERS Logs whether a regex rule wasn't indexed since it exceeded the per-rule memory limit. Emitted for every regex rule an extension adds. Note: this histogram was expired from 2025-03-17 to 2025-03-25; data may be missing. kelvinjiang@chromium.org src/extensions/OWNERS Emitted when an extension ruleset has finished loading for the Declarative Net Request API. Records if the extension version at the start of the ruleset load matches the version at the end. kelvinjiang@chromium.org src/extensions/OWNERS Records the result of loading an extension ruleset for the Declarative Net Request API. Emitted whenever a single extension ruleset is loaded. kelvinjiang@chromium.org extensions-core@chromium.org The number of enabled indexed declarative rules provided by an extension manifest for the Declarative Net Request API. This is emitted whenever a packaged extension with a declarative ruleset is installed or updated. kelvinjiang@chromium.org extensions-core@chromium.org Indicates the result of reading the dynamic JSON rules for an extension from the disk. Logged whenever an extension calls the getDynamicRules extension function or when it updates the dynamic rules through a call to addDynamicRules or removeDynamicRules. Note: this histogram was expired from 2023-06-01 to 2023-09-01; data may be missing. quarz@chromium.org src/extensions/OWNERS Logs the type of redirect action when a request is redirected by the Declarative Net Request API. Logged whenever a navigation or resource request is redirected. kelvinjiang@chromium.org src/extensions/OWNERS Indicates whether RulesMonitorService::ApiCallQueue::SetReadyToExecuteApiCalls() has already been called before. Recorded on each call of SetReadyToExecuteApiCalls(). The intended behavior is that there are no redundant SetReadyToExecuteApiCalls() calls. See crbug.com/358617943. kelvinjiang@chromium.org src/extensions/OWNERS The time taken to evaluate regex rules for a single declarativeNetRequest ruleset where the ruleset has {RegexRulesetSize}, before the request was sent. Emitted once per ruleset per evaluated request. This is recorded only for clients with high-resolution clocks. kelvinjiang@chromium.org src/extensions/OWNERS For a single declarativeNetRequest ruleset, the percent of the total amount of time spent on evaluating regex rules, before the request was sent (in the onBeforeRequest stage). Emitted once per ruleset per evaluated request if the ruleset has at least one regex rule. kelvinjiang@chromium.org src/extensions/OWNERS The time taken to evaluate regex rules for a single declarativeNetRequest ruleset where the ruleset has {RegexRulesetSize}, after the request has received response headers. Emitted once per ruleset per evaluated request. This is recorded only for clients with high-resolution clocks. kelvinjiang@chromium.org src/extensions/OWNERS For a single declarativeNetRequest ruleset, the percent of the total amount of time spent on evaluating regex rules, after the request has received response headers. Emitted once per ruleset per evaluated request if the ruleset has at least one regex rule. kelvinjiang@chromium.org extensions-core@chromium.org Logs the size of a regex rule in bytes, including rules that exceed the per-rule memory limit that aren't indexed. Note that any rules above 100Kb are recorded as 100Kb. Emitted for every regex rule an extension adds. rdevlin.cronin@chromium.org kelvinjiang@chromium.org src/extensions/OWNERS Records the request header added by extensions using the DeclarativeNetRequest API. Recorded for each network request during the OnBeforeSendHeaders stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org kelvinjiang@chromium.org src/extensions/OWNERS Records the request header modified by extensions using the DeclarativeNetRequest API. Recorded for each network request during the OnBeforeSendHeaders stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org kelvinjiang@chromium.org src/extensions/OWNERS Records the request header removed by extensions using the DeclarativeNetRequest API. Recorded for each network request during the OnBeforeSendHeaders stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org kelvinjiang@chromium.org src/extensions/OWNERS Records the response header added by extensions using the DeclarativeNetRequest API. Recorded for each network request during the OnHeadersReceived stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org kelvinjiang@chromium.org src/extensions/OWNERS Records the response header modified by extensions using the DeclarativeNetRequest API. Recorded for each network request during the OnHeadersReceived stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org kelvinjiang@chromium.org src/extensions/OWNERS Records the response header removed by extensions using the DeclarativeNetRequest API. Recorded for each network request during the OnHeadersReceived stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org kelvinjiang@chromium.org src/extensions/OWNERS The time taken to determine the appropriate declarativeNetRequest action for a given request from a single ruleset in an extension where the ruleset has {RulesetSize}, before the request was sent. This is recorded only for clients with high-resolution clocks. rdevlin.cronin@chromium.org kelvinjiang@chromium.org src/extensions/OWNERS The time taken to determine the appropriate declarativeNetRequest action for a given request from a single ruleset in an extension where the ruleset has {RulesetSize}, after the request has received response headers. This is recorded only for clients with high-resolution clocks. kelvinjiang@chromium.org extensions-core@chromium.org Indicates whether reindexing of a Declarative Net Request ruleset was successful. Called whenever a JSON ruleset for an extension is reindexed, e.g. on ruleset corruption. Note: this is emitted for both static and dynamic rulesets. rdevlin.cronin@chromium.org kelvinjiang@chromium.org extensions-core@chromium.org Indicates the result of an extension function call to add or remove dynamic rules. Logged every time an extension calls the addDynamicRules or removeDynamicRules extension function. Note: this histogram was expired from 2023-06-26 to 2023-09-01; data may be missing. jlulejian@chromium.org extensions-core@chromium.org Logged once on profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). This emits true if the user has extension developer mode enabled. Note: this is only on profile open, so if a user either 1) later enables dev mode or 2) enables dev mode after profile start and disables it before the next profile start we emit false once in either scenario. richche@chromium.org chrome-counter-abuse-alerts@google.com The current developer mode status of the main profile. Recorded for all UMA logs at upload time by the ExtensionsMetricsProvider. This is also used as the "Extensions Developer Mode Status" filter in the UMA dashboard. rdevlin.cronin@chromium.org extensions-core@chromium.org Part of the suite of Extensions.DidCreateScriptContext_* metrics. Records the time taken to install Extension JavaScript bindings per blessed extension context (chrome-extension://... origins within Extension processes, like background pages, options pages, popups). rdevlin.cronin@chromium.org extensions-core@chromium.org Part of the suite of Extensions.DidCreateScriptContext_* metrics. Records the time taken to install Extension JavaScript bindings per blessed web page context (hosted apps). rdevlin.cronin@chromium.org extensions-core@chromium.org Part of the suite of Extensions.DidCreateScriptContext_* metrics. Records the time taken to install Extension JavaScript bindings per content script context. rdevlin.cronin@chromium.org extensions-core@chromium.org Part of the suite of Extensions.DidCreateScriptContext_* metrics. Records the time taken to install Extension JavaScript bindings per content script context. This histogram measures the time to install Extension Javascript bindings in a context for a platform app enabled on the Chrome OS lock screen. rdevlin.cronin@chromium.org extensions-core@chromium.org Part of the suite of Extensions.DidCreateScriptContext_* metrics. Records the time taken to install Extension JavaScript bindings per unblessed extension context (chrome-extension://... origins hosted in iframes). rdevlin.cronin@chromium.org extensions-core@chromium.org Part of the suite of Extensions.DidCreateScriptContext_* metrics. Records the time taken to install Extension JavaScript bindings in an unknown type of context (this should never happen other than in bizarre circumstances). rdevlin.cronin@chromium.org extensions-core@chromium.org Part of the suite of Extensions.DidCreateScriptContext_* metrics. Records the time taken to install Extension JavaScript bindings per web page context (just the chrome.app, chrome.webstore, and possibly chrome.runtime APIs). rdevlin.cronin@chromium.org extensions-core@chromium.org Part of the suite of Extensions.DidCreateScriptContext_* metrics. Records the time taken to install Extension JavaScript bindings per WebUI context (chrome://extensions and so forth). rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions that are disabled at browser profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions that are disabled at browser profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) due to permissions increases. rdevlin.cronin@chromium.org extensions-core@chromium.org The count of disabled extensions on profile open grouped by disble reason from disable_reason::DisableReason. When an extension is disabled, it can be for one or more reasons (although typically just one), so the sum of these may be greater than 'Extensions.Disabled' which is a count of the number of unique extensions that are disabled. rdevlin.cronin@chromium.org extensions-core@chromium.org The count of disabled extensions on profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). Grouped by disable reason from disable_reason::DisableReason. When an extension is disabled, it can be for one or more reasons (although typically just one), so the sum of these may be greater than 'Extensions.Disabled' which is a count of the number of unique extensions that are disabled. jeffcyr@google.com chrome-counter-abuse-alerts@google.com Reports the value of the Safe Browsing CRX allowlist custom omaha attribute when an update check occurs for an extension. rdevlin.cronin@chromium.org extensions-core@chromium.org The time between an extension's event page loading its first URL and the event page later shutting down. rdevlin.cronin@chromium.org extensions-core@chromium.org The time taken for an extension's event page to load its initial URL. jlulejian@chromium.org extensions-core@chromium.org Records whether an event dispatched through the event router was acked by the renderer within a 5 minute threshold for background context of type {BackgroundContextType}. Emits true shortly after extensions browser code receives the ack from the renderer if within that threshold. Emits false if that ack hasn't occurred within the threshold. The 5 minute upper bound was chosen based on when the majority of events are ack'd. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded every time an event is dispatched to an extension. jlulejian@chromium.org extensions-core@chromium.org Records the time it took for the event to be sent to the event router for dispatch for background page of type {BackgroundContextType}. Reports samples at milliseconds granualarity up to 1 day. This is meant to investigate an appropriate time maximum for Extensions.Events.DispatchToAckTime.{BackgroundContextType}. It does not include any requests that utilize the EventRouter::DispatchEventToSender() event routing flow (some web request API, and web view API events). jlulejian@chromium.org extensions-core@chromium.org Records the time it took for the event to be sent to the event router for dispatch for background page of type event page{ContextActive}. Emitted when extensions browser code receives receives an ack from the renderer that it fired the event in the event page. It only counts events that ran in a event page background script, other listeners in the extension renderer that can receive the event are not counted. Reports samples at microseconds granualarity up to 5 minutes. Values over 5 minutes are bucketed together since no ack is expected to take longer than that. 5 minutes was decided since that is the maximum for extension service worker event lifetime. This is recorded only for clients with high-resolution clocks. It does not include any requests that utilize the EventRouter::DispatchEventToSender() event routing flow (some web request API, and web view API events). Note: Previous version replaced October, 2023 because values were inaccurate due to a bug where we recorded this metric for all events for an extension, rather that just for those that ran in the lazy background page script. jlulejian@chromium.org extensions-core@chromium.org Note: Separate from Extensions.Events.DispatchToAckTime.{BackgroundContextType}{ContextActive} because PersistentBackgroundPages are always active (and thus don't need a ContextActive variant). Records the time it took for the event to be sent to the event router for dispatch for background page of type persistent background page. Emitted shortly after extensions browser code receives the ack from the renderer that it fired the event in the persistent background page. "shortly" because there is an IPC call between dispatching the event in the renderer and the acknowledgement by the browser side that emits the value. Reports samples at microseconds granualarity up to 5 minutes. Values over 5 minutes are bucketed together since no ack is expected to take longer than that. 5 minutes was decided since that is the maximum for extension service worker event lifetime. This is recorded only for clients with high-resolution clocks. It does not include any requests that utilize the EventRouter::DispatchEventToSender() event routing flow (some web request API, and web view API events). jlulejian@chromium.org extensions-core@chromium.org Records the time it took for the event to be sent to the event router for dispatch for a background page of type service worker{ContextActive}. Emitted shortly after extensions browser code receives the ack from the renderer that it fired the event in the service worker. "shortly" because there is a function call between the receipt by the browser and recording the value. Note: this may include some amount of execution time of the extension service worker JS listener. Reports samples at microseconds granualarity up to 5 minutes. Values over 5 minutes are bucketed together since no ack is expected to take longer than that. 5 minutes was decided since that is the maximum for extension service worker event lifetime. This is recorded only for clients with high-resolution clocks. It does not include any requests that utilize the EventRouter::DispatchEventToSender() event routing flow (some web request API, and web view API events). If the extension was unloaded when the event was dispatched, the worker is considered inactive. Note: this histogram was incremented May, 2024 since it additionally started emmitting when the extension is unloaded. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded every time an event is dispatched to a *component* extension. Otherwise identical to Extensions.Events.Dispatched. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded every time an event is dispatched to an extension with a persistent background page. The event may or may not have been dispatched to the background page itself, for example it may have been dispatched to its popup. When this metric is recorded, Extensions.Events.Dispatch will also be recorded. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded every time an event is dispatched to an extension with an event page that was already running (i.e. at some point had been woken from its suspended state, see Extensions.Events.DispatchWithSuspendedEventPage). The event may or may not have been dispatched to the event page itself, for example it may have been dispatched to its popup. When this metric is recorded, Extensions.Events.Dispatch will also be recorded. jlulejian@chromium.org extensions-core@chromium.org Recorded every time an event is dispatched to a service worker based extension background context. When this metric is recorded, Extensions.Events.Dispatch will also be recorded. Warning: this histogram was expired from 2022-12 to 2023-11; data will be missing during this timeframe. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded every time an event is dispatched to an extension with an event page that was suspended. This implies that firing this event woke up the event page. The event may or may not have been dispatched to the event page itself, for example it may have been dispatched to its popup, but regardless it will wake the event page. When this metric is recorded, Extensions.Events.Dispatch will also be recorded. jlulejian@chromium.org extensions-core@chromium.org Emits the event type that failed when Extensions.Events.DidDispatchToAckSucceed.ExtensionServiceWorker2 == false. jlulejian@chromium.org extensions-core@chromium.org Emits whether the ServiceWorkerContext::StartingExternalRequest() succeeded or failed when Extensions.Events.DidDispatchToAckSucceed.ExtensionServiceWorker2 == false. Note there is missing data during 2024-04 since the metric was not emitting temporarily. jlulejian@chromium.org extensions-core@chromium.org Emits the ServiceWorkerExternalRequestResult when Extensions.Events.ServiceWorkerDispatchFailed.StartExternalRequestOk == false. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Recorded when a new violation is retrieved from Omaha for an extension. The new violation reason is retrieved from the update service data key reasons during an update check for extensions. This metric was added in M92 to replace the old version, because the logic of logging greylisted extensions has changed. Warning: this histogram was expired from 2024-08-11 to 2025-11-13; data may be missing. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Number of cached extensions on disk. Reported on Chrome OS during user session start. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Total size of .crx files in cache on disk. Reported on Chrome OS during user session start. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Recorded when an extension that was previously enabled is disabled due to a new violation retrieved from Omaha. This is recorded when the violation is detected when Chrome checks for an update for the extension. This metric was added in M92 to replace the old version, because the logic of logging greylisted extensions has changed. Warning: this histogram was expired from 2024-08-11 to 2025-11-13; data may be missing. rdevlin.cronin@chromium.org Emitted when an extension is downloaded by the user (including webstore installs). jlulejian@chromium.org extensions-core@chromium.org Counts when an extension is downloaded by the user from the webstore and no currently installed extensions (if any) were installed from the webstore. Emitted after an extension has successfully finished installing. rdevlin.cronin@chromium.org extensions-core@chromium.org The install location for a given extension. Recorded once per enabled extension on profile initialization for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). richche@chromium.org anunoy@chromium.org chrome-counter-abuse-alerts@google.com Recorded when an extension that was previously only disabled remotely is re-enabled remotely during an update service session. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Recorded when a {BlocklistState} extension that was previously only disabled remotely is re-enabled remotely during an update service session. Warning: this histogram was expired from 2024-06-18 to 2025-11-13; data may be missing. anunoy@chromium.org The number of sideloaded apps/extensions loaded on profile open grouped by enabled/disabled state. Histogram is in the process of being removed in favor of its incremented version that emits only on profile open for "user" profiles (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). Warning: this histogram was expired from 2023-07-07 to 2025-11-13; data may be missing. anunoy@chromium.org extensions-core@chromium.org The number of sideloaded apps/extensions loaded on profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). Grouped by enabled/disabled state. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions (and friends) that could have been given access to the file:// scheme, and were, for users that have at least one extension that could have been given access. This excludes anything that doesn't show up in chrome://extensions (platform apps, hosted apps, component extensions), policy-installed extensions, and unpacked extensions. Logged once per profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). See also Extensions.FileAccessNotAllowed. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions (and friends) that could have been given access to the file:// scheme, but weren't, for users that have at least one extension that could have been given access. This excludes anything that doesn't show up in chrome://extensions (platform apps, hosted apps, component extensions), policy-installed extensions, and unpacked extensions. Logged once per profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). See also Extensions.FileAccessAllowed. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Number of enterprise policy forced extensions that are blocklisted and thus not loaded 5 minutes after profile creation if at least one of policy forced extensions is not yet enabled. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com Status of cache entry about enterprise policy forced extension. Recorded for each forced extension. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The last known intermediate stage of extension when the extension installation stage if CREATED if failure reason was not recorded (installation of an extension was neither yet finished nor failed). Recorded for each forced extension that failed to install after 5 minutes. Recorded together with "Extensions.ForceInstalledTimedOutCount" histogram, but for every extension not installed at the moment. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The last known downloading stage of extension downloading process if failure reason was not recorded and installing stage is DOWNLOADING, so it's specification of Extensions.ForceInstalledStage. Recorded for each forced extension that failed to install after 5 minutes. Recorded together with "Extensions.ForceInstalledTimedOutCount" histogram, but for every extension not installed at the moment. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Status of cache entry about enterprise policy forced extension which failed to install. Recorded for each forced extension that failed to install after 5 minutes. Recorded together with "Extensions.ForceInstalledTimedOutCount" histogram, but for every extension not installed at the moment. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Detailed reason why CRX installation failed for enterprise policy forced extensions. Recorded for each forced extension that failed to install after 5 minutes with Extensions.{OffStore,Webstore}_ForceInstalledFailureReason3 equal to CRX_INSTALL_ERROR_*. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The detailed reason why enterprise policy forced extensions had failed to install because fetched update manifest was invalid due to app status error. Recorded for each forced extension that failed to install after 5 minutes with Extensions.ForceInstalledFailureReason2 equal to MANIFEST_INVALID and Extensions.ForceInstalledFailureManifestInvalidErrorDetail2 equal to BAD_APP_STATUS. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The info field in the update manifest fetched from the server for enterprise policy forced extensions. Recorded for each forced extension for which the server responds with no updates and an empty CRX fetch url. Recorded for each forced extension that failed to install after 5 minutes with Extensions.{OffStore,WebStore}_ForceInstalledFailureReason3 equal to CRX_FETCH_URL_EMPTY. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The reason why enterprise policy forced extensions had failed to unpack. Recorded for each forced extension that failed to install after 5 minutes with Extensions.ForceInstalledFailureReason3 equal to CRX_INSTALL_ERROR_SANDBOXED_UNPACKER_FAILURE. Replaced Extensions.ForceInstalledFailureSandboxUnpackFailureReason because the enum values were not in sync with the C++ enums. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The type of session in case enterprise policy forced extensions were not installed. Recorded for each force installed extension which failed to install after 5 minutes. Supported only on ChromeOS and recorded only if there is an active user. {FailureReason} giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Records whether the extensions are enabled or not. Recorded for each forced extension that failed to install after 5 minutes with Extensions.ForceInstalledCreationStage equal to NOTIFIED_FROM_MANAGEMENT_INITIAL_CREATION_FORCED. Replaced "Extensions.ForceInstalledFailureStuckInCreatedStageAreExtensionsEnabled" because the histogram collects data about extensions stuck in NOTIFIED_FROM_MANAGEMENT_INITIAL_CREATION_FORCED stage but the name suggested that the data is collected for extensions stuck in CREATED stage. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Records whether the extension is from the Chrome Web Store or not. Recorded for each forced extension that failed to install after 5 minutes with Extensions.ForceInstalledFailureSandboxUnpackFailureReason equal to CRX_HEADER_INVALID. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Records whether the extension is downloaded from cache or not. Recorded for each forced extension that failed to install after 5 minutes with Extensions.ForceInstalledFailureSandboxUnpackFailureReason equal to CRX_HEADER_INVALID. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The amount of time elapsed during installation of enterprise policy forced extensions. richche@google.com chrome-counter-abuse-alerts@google.com Records the higher of two values, trust level for the machine or that of the user profile. The trust level is determined by the management authority, such as local device, non-local, cryptographically verifiable policy source, etc. This histogram is emitted when all the force-installed extensions are ready to use. Recorded for only Windows and Mac. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Records the disable reason for the enterpise policy forced extensions. Recorded for each forced extension that installed but failed to load after 5 minutes. If the extension is not disabled, it records DisableReason::DISABLE_NONE. erikchen@chromium.org extensions-core@chromium.org Called once each time the user clicks the accept button on the force-installed, pre-installed deprecated apps dialog. This results in the browser opening a new tab with a URL to one of 6 pre-defined sites. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The amount of time elapsed for enterprise policy forced extensions to become ready for use. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Records whether there was a possible non-misconfiguration failure for the enterprise policy forced extensions. Records true if in a session at least one forced extension failed to install after 5 minutes with a non-misconfiguration failure and false when all the forced extensions which failed to install after 5 minutes failed due to some misconfiguration. Recorded together with "Extensions.ForceInstalledTimedOutCount" histogram. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The last known stage of extension installation process if failure reason was not recorded (installation of an extension was neither yet finished nor failed). Recorded for each forced extension that failed to install after 5 minutes. Recorded together with "Extensions.ForceInstalledTimedOutCount" histogram, but for every extension not installed at the moment. Replaced Extensions.ForceInstalledStage because the stages that were used for used for investigation of CREATED stage are moved to a new enum. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Number of enterprise policy forced extensions that are not installed after 5 minutes if at least one of policy forced extensions is not yet enabled. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Number of enterprise policy forced extensions that are not loaded after 5 minutes timeout, while might be already installed. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The amount of time elapsed during different stage of the installation process for the enterprise policy forced extensions. {ExtensionInstallStages} giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Total amount of extensions in force installed list. Gets recorded on profile open (which happens on every startup and when user logs in) and tries to load extensions. Number of records should correspond to the sum of records in "Extensions.ForceInstalledLoadTime" and records in "Extensions.ForceInstalledTimedOutAndNotInstalledCount". giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Number of fetch retries made when enterprise policy forced extensions failed to install with {ErrorType}. Recorded for each forced extension that failed to install after 5 minutes with Extensions.`OffStore,Webstore`_ForceInstalledFailureReason3 equal to {ErrorType}. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com Network error code for the last retry attempt when CRX fetch failed for enterprise policy forced extensions failed to install due to {ErrorType}. Recorded for each forced extension that failed to install after 5 minutes with Extensions.`OffStore,WebStore`_ForceInstalledFailureReason3 equal to {ErrorType}. anunoy@chromium.org extensions-core@chromium.org Number of apps/extensions loaded on profile open with an inconsistent "from webstore" state for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). This means an item that is flagged as from_webstore, but with either a non-webstore update_url or an external install location. Warning: this histogram was expired from 2025-03-02 to 2025-11-13; data may be missing. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when a component extension calls an extension API. Recorded once per function call. See also Extensions.Functions.WebUICalls, Extensions.Functions.WebUIUntrustedCalls, Extensions.Functions.NonExtensionWebPageCalls and Extensions.Functions.ExtensionCalls. kelvinjiang@chromium.org extensions-core@chromium.org Recorded when an error is thrown from a developerPrivate API function when there is no extension with the specified ID found. Used to pinpoint which functions may be causing most crashes as seen in crbug.com/431205004 when this error is thrown. wjmaclean@chromium.org rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when a component extension calls an extension API from within a sandboxed frame. Recorded once per function call to track how often API functions are called within sandboxed frames. See Extensions.Functions.ComponentExtensionCalls, for comparison with the total number of calls from a component extension to an extension API. wjmaclean@chromium.org rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when a non-component extension calls an extension API from within a sandboxed frame. Recorded once per function call to track how often API functions are called within sandboxed frames. See Extensions.Functions.ExtensionCalls, for comparison with the total number of calls from a non-component extension to an extension API. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when a non-component extension calls an extension API. Recorded once per function call. See also Extensions.Functions.WebUICalls, Extensions.Functions.WebUIUntrustedCalls, Extensions.Functions.NonExtensionWebPageCalls and Extensions.Functions.ComponentExtensionCalls. tjudkins@chromium.org rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when a manifest V3 extension calls an extension API. Note that the function would also be included in either Extensions.Functions.ExtensionCalls or Extensions.Functions.ComponentExtensionCalls histogram. lazyboy@chromium.org dbertoni@chromium.org rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when an extension service worker calls an extension API. Note that the function would also be included in either Extensions.Functions.ExtensionCalls or Extensions.Functions.ComponentExtensionCalls histogram. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when an extension function call fails and finishes execution. The suffix indicates the exact bucket the function is in. See also Extensions.Functions.FailedTotalExecutionTime. {ExtensionFunctionExecutionTime} rdevlin.cronin@chromium.org extensions-core@chromium.org The amount of time it takes to handle a response for an extension API request. Recorded on the renderer side once we receive the response IPC from the browser and have deserialized the arguments and passed them to the JS context. Only recorded if the response is successfully handled. tjudkins@chromium.org rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when a Web Page context not associated with an extension calls an extension API. Generally extension APIs are only exposed to extensions or WebUI, but there are rare cases where an API is exposed to a web page not associated with an extension e.g. the Chrome Webstore. Recorded once per function call. See also Extensions.Functions.WebUICalls, Extensions.Functions.WebUIUntrustedCalls, Extensions.Functions.ComponentExtensionCalls and Extensions.Functions.ExtensionCalls. rdevlin.cronin@chromium.org extensions-core@chromium.org The amount of time it takes to start an extension API request. Recorded on the renderer side after we perform JS pre-processing, but includes all serialization and dispatching. Only recorded if the request is successfully dispatched. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when an extension function call succeeds and finishes execution. The suffix indicates the exact bucket the function is in. See also Extensions.Functions.SucceededTotalExecutionTime. {ExtensionFunctionExecutionTime} rdevlin.cronin@chromium.org extensions-core@chromium.org The total amount of time it took to execute an extension function that succeeded from the time the extension function is called to the time the function responds. Note that since some extension functions are inherently slow (anything that requires user interaction, for instance), this is not a definitive source for function performance. rdevlin.cronin@chromium.org extensions-core@chromium.org The synchronous amount of time an extension function takes. Note that many extension functions run asynchronously; see also Extensions.Functions.[Succeeded|Failed]TotalExecutionTime. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when a WebUI context calls an extension API. Recorded once per function call. See also Extensions.Functions.WebUIUntrustedCalls, Extensions.Functions.NonExtensionWebPageCalls, Extensions.Functions.ComponentExtensionCalls and Extensions.Functions.ExtensionCalls. rdevlin.cronin@chromium.org extensions-core@chromium.org Recorded when a WebUI context calls an extension API. Recorded once per function call. See also Extensions.Functions.WebUICalls, Extensions.Functions.NonExtensionWebPageCalls, Extensions.Functions.ComponentExtensionCalls and Extensions.Functions.ExtensionCalls. arabm@chromium.org chrome-incognito@google.com This histogram records requests to use resources from Google Docs Offline extension, along with whether the extension has been available or not and the request has been done from incognito mode or not. Note that this request is double counted for the imports. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Emits the Extension::Location of a newly-disabled greylisted extension. Logged when SafeBrowsingVerdictHandler greylists and disables an installed extension. Warning: this histogram was expired from 2024-09-07 to 2025-11-13; data may be missing. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Emits the Extension::Location of an extension that was ungreylisted. Logged when SafeBrowsingVerdictHandler ungreylists and enables an installed extension. Warning: this histogram was expired from 2024-09-07 to 2025-11-13; data may be missing. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Records the enabled state of a greylisted force-installed extension in a {TrustLevel} management environment. A greylisted extension is one that has been taken down by the Chrome Web Store for non-malware reasons such as store policy violations or unwanted software categorization. Recorded once per extension at profile startup on Windows and macOS. Only applicable for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). rdevlin.cronin@chromium.org extensions-core@chromium.org Whether there were any permissions present in an extension when it was installed for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). To find places where this histogram may be emitted, look for calls to InstalledLoader::RecordPermissionMessagesHistogram with the argument Install. For Sync users, this is reported for each device. rdevlin.cronin@chromium.org extensions-core@chromium.org Whether there were any permissions present in an extension when it was loaded (which happens at profile open or extension install) for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). To find places where this histogram may be emitted, look for calls to InstalledLoader::RecordPermissionMessagesHistogram with the argument Load. rdevlin.cronin@chromium.org kelvinjiang@chromium.org junhaohuang@microsoft.com The number of enabled extensions with a homepage override specified in their manifest. Recorded once per "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) at profile initialization. benwells@chromium.org dominickn@chromium.org Records the container used for a hosted app launch, when the app is launched. The definition of 'launch' for the purposes of this histogram is different to that used for the launch type histograms. This definition is less inclusive, for example it does not include navigations to the hosted app due to normal browsing, which the other definition does include. This definition could be thought of more as explicit launches via a launch surface such as the app launcher, chrome://apps, or a shortcut. evasu@chromium.org extensions-core@chromium.org Records the host permissions access for a enabled extension as a result of the RuntimeHostPermissions feature. Recorded once per extension at profile initialization for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. evasu@chromium.org extensions-core@chromium.org Records the host permissions access for each enabled extension that specifies a host permission that matches an effective TLD. Recorded once per extension at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. evasu@chromium.org extensions-core@chromium.org Records the host permissions access for each enabled extension that specifies hosts, but has no host permission that matches an effective TLD. Recorded once per extension at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions (and friends) that could have been allowed in incognito, and were, for users that have at least one extension that could have been allowed. This excludes anything that doesn't show up in chrome://extensions (platform apps, hosted apps, component extensions), policy-installed extensions, and unpacked extensions. Logged at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. rdevlin.cronin@chromium.org extensions-core@chromium.org The amount of time for a CSS file to be injected into a page. rdevlin.cronin@chromium.org extensions-core@chromium.org Time taken to execute all scripts for one location within an extension. Recorded every time content scripts injected by extensions are executed {UserScriptRunLocation}. Unlike Extensions.InjectScriptTime, this includes execution time of asynchronously injected scripts. rdevlin.cronin@chromium.org Number of blocking scripts injected at document end by extensions. rdevlin.cronin@chromium.org Number of scripts injected at document end by extensions. rdevlin.cronin@chromium.org extensions-core@chromium.org Time taken to inject all scripts at document end by extensions. Not reported if scripts are executed asynchronously. rdevlin.cronin@chromium.org Number of blocking scripts injected at document idle by extensions. rdevlin.cronin@chromium.org Number of scripts injected at document idle by extensions. rdevlin.cronin@chromium.org extensions-core@chromium.org Time taken to inject all scripts at document idle by extensions. Not reported if scripts are executed asynchronously. rdevlin.cronin@chromium.org extensions-core@chromium.org Number of blocking scripts injected at document start by extensions. rdevlin.cronin@chromium.org Number of css files injected by extensions. rdevlin.cronin@chromium.org extensions-core@chromium.org Number of scripts injected at document start by extensions. rdevlin.cronin@chromium.org Time taken to inject css/scripts at document start by extensions. Not reported if scripts are executed asynchronously. evasu@chromium.org extensions-core@chromium.org Logged every time an extension is installed. Records the reason why the extension was or wasn't automatically pinned to the toolbar. jeffcyr@google.com chrome-counter-abuse-alerts@google.com Action taken in the extension install friction dialog displayed to Enhanced Safe Browsing users before installing an extension that is not included in the Safe Browsing CRX allowlist. Warning: this histogram was expired from 2024-11-17 to 2025-01-07; data may be missing. rdevlin.cronin@chromium.org extensions-core@chromium.org Installs grouped by the location property in prefs for {UserType}. Emitted once per profile open. rdevlin.cronin@chromium.org extensions-core@chromium.org Installs grouped by Extension::HistogramType for {UserType}. Emitted once per extension install. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions and themes loaded at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org Time taken to load all component extensions at profile open. This happens as part of the total initialization time of ExtensionService, measured in Extensions.ExtensionServiceInitTime. Histogram is in the process of being removed in favor of its new versions (Extensions.LoadAllComponentTime.NonUser and Extensions.LoadAllComponentTime.User) that emit only on profile open for "user" profiles (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). rdevlin.cronin@chromium.org extensions-core@chromium.org Time taken to load all component extensions at profile open for non-"user profiles" (profiles where people cannot install extensions, specifically profiles that can only have component extensions installed). This happens as part of the total initialization time of ExtensionService, measured in Extensions.ExtensionServiceInitTime. Emitted once per profile open. rdevlin.cronin@chromium.org extensions-core@chromium.org Time taken to load all component extensions at profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). This happens as part of the total initialization time of ExtensionService, measured in Extensions.ExtensionServiceInitTime. Emitted once per profile open. rdevlin.cronin@chromium.org extensions-core@chromium.org Time taken to load all non-component extensions at profile open and record metrics for non-"user profiles" (profiles where people cannot install extensions, specifically profiles that can only have component extensions installed). This happens as part of the total initialization time of ExtensionService, measured in Extensions.ExtensionServiceInitTime. Emitted once per profile open. rdevlin.cronin@chromium.org extensions-core@chromium.org Time taken to load all non-component extensions at profile open and record metrics for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). This happens as part of the total initialization time of ExtensionService, measured in Extensions.ExtensionServiceInitTime. Emitted once per profile open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of apps loaded by each user at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org The number of externally managed apps loaded by each user at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of user-installed apps loaded by each user at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of browser action extensions loaded at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions loaded at profile open for "user" profiles (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). rdevlin.cronin@chromium.org The number of externally managed extensions loaded at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of user-installed extensions loaded at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org The number of externally managed extensions and apps loaded at profile open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of hosted apps loaded by each user at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. richche@chromium.org chrome-counter-abuse-alerts@google.com Recorded when extension are loaded via the "--load-extension" or "--disable-extensions-except" command line switch. Emitted once per profile start while extensions are loading with flags present, and the extension is loaded without being blocked. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions that had neither a page nor browser action specified in their manifest. Recorded at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of enabled extensions or apps the user has installed that do not update from the Chrome Web Store. Recorded during "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. rdevlin.cronin@chromium.org The number of legacy packaged apps loaded by each user at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org The number of platform apps loaded at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of themes loaded at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions loaded at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open grouped by Extension::HistogramType. solomonkinard@chromium.org extensions-core@chromium.org Emitted whenever an extension calls the chrome.management.setEnabled() API method. Emits whether API call was made using a user gesture. jam@chromium.org cduvall@chromium.org Measures how long ExtensionManagement::Refresh takes. This reloads all enterprise-related policies for all extensions, and is called both at startup and any time the enterprise policy changes. rdevlin.cronin@chromium.org extensions-core@chromium.org The manifest version of each loaded extension. Emitted for each extension at "user profils" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. Note: Though the histogram name is 'Extensions.ManifestVersion2', it does not represent MV2. Instead, it represents the second version of the histogram that was named 'Extensions.ManifestVersion'. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of enabled manifest version 2 {ManifestLocation}. Emitted once on profile startup for user profiles (profiles where users can install extensions, specifically profiles that can have non-component extensions installed). rdevlin.cronin@chromium.org extensions-core@chromium.org The number of enabled manifest version 3 {ManifestLocation}. Emitted once on profile startup for user profiles (profiles where users can install extensions, specifically profiles that can have non-component extensions installed). rdevlin.cronin@chromium.org extensions-core@chromium.org The manifest version of an enabled {ManifestLocation}. Emitted for every enabled extension (not for other extension-y items, like platform apps) on profile startup for user profiles (profiles where users can install extensions, specifically profiles that can have non-component extensions installed). andreaorru@chromium.org jlulejian@chromium.org extensions-core@chromium.org Tracks that for every IPC we dispatch to create a port for a messaging channel in the renderer whether it responded, or if the channel or port closed before the ack could be received. Emitted each time a (LocalFrame::|ServiceWorker::)DispatchOnConnect IPC is dispatched to a {DispatchTarget}. This occurs once for every available frame and worker in the extension when a channel is opened to an extension. It is permuted by channel type (message type). {ChannelType}. Note: a new enum value was added in February 2026, which could affect query results across that date. Note: This histogram was expired during February 2026 so some data might be missing. andreaorru@chromium.org jlulejian@chromium.org extensions-core@chromium.org Tracks the results of attempting to open a channel to an extension. Emitted each time a messaging channel is opened which occurs once per messaging communication (one-time or long-lived connections). It is permuted by worker status. Specifically if an extension has {WorkerStatus}. It is permuted by channel type (message type). {ChannelType} Note: a new enum value was added in February 2026, which could affect query results across that date. andreaorru@chromium.org jlulejian@chromium.org extensions-core@chromium.org Tracks that when a messaging channel is opened to a worker-based extension, whether the extension was able to create a port (for any listener, not necessarily the worker). Emitted each time a messaging channel is opened which occurs once per messaging communication (one-time or long-lived connections). It is permuted by channel type (message type). {ChannelType}. Note: a new enum value was added in February 2026, which could affect query results across that date. Note: This histogram was expired From July to February 2026 so some data might be missing. andreaorru@chromium.org jlulejian@chromium.org extensions-core@chromium.org Tracks whether a worker was successfully started in order to open a channel to the worker-based extension. Emitted each time a messaging channel is opened which occurs once per messaging communication (one-time or long-lived connections). It is permuted by channel type (message type). {ChannelType}. Note: a new enum value was added in February 2026, which could affect query results across that date. Note: This histogram was expired From July to February 2026 so some data might be missing. kelvinjiang@chromium.org extensions-core@chromium.org Number of enabled extensions which have requested the "nativeMessaging" permission. Includes all kinds of extensions, including component and unpacked extensions. Recorded during "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. rdevlin.cronin@chromium.org src/extensions/OWNERS The state of a given MV2 extension on a user's device. Emitted once after profile initialization for user profiles (profiles where users can install extensions, specifically profiles that can have non-component extensions installed). Emitted only if the user is in an MV2 experiment stage that can disable MV2 extensions. Only emitted for non-component MV2 extensions. kelvinjiang@chromium.org extensions-core@chromium.org The size of the message in bytes sent from {NativeMessagingSource} for native messaging. Recorded only for native hosts launched via host manifest files on desktop platforms. jkokatsu@google.com extensions-core@chromium.org Counts usage of various schemes (e.g. file:, chrome:, http:) when a navigation is triggered from an extension (such as through tabs API). rdevlin.cronin@chromium.org kelvinjiang@chromium.org src/extensions/OWNERS Time that network requests were blocked due to extensions. battre@chromium.org src/extensions/OWNERS Percentage of total lifetime a network request was blocked due to an extension. rdevlin.cronin@chromium.org kelvinjiang@chromium.org The number of enabled extensions with a New Tab Page override specified in their manifest. Recorded once per "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) at profile open. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of apps/extensions with a non-webstore update_url loaded on profile open grouped by Extension::Location. Emitted per "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. richche@google.com chrome-counter-abuse-alerts@google.com The number of {ExtensionState} non-webstore extensions with a non-webstore update_url loaded on profile open and {DeveloperModeState}. Grouped by Extension::Location. Emitted on every profile open only for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). This replaces the previous histogram, NonWebstoreLocationWith{DeveloperModeState}{ExtensionState}2, due to missing data from M126. anunoy@chromium.org extensions-core@chromium.org Number of non-WebStore extensions on profile open for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) that override the new tab page. jeffcyr@google.com chrome-counter-abuse-alerts@google.com The total number of disabled extensions that are not present in the Enhanced Safe Browsing CRX allowlist. Recorded for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) on profile initialization. jeffcyr@google.com chrome-counter-abuse-alerts@google.com The total number of disabled extensions that are not present in the Enhanced Safe Browsing CRX allowlist. Recorded for only for Enhanced Safe Browsing users on "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. jeffcyr@google.com chrome-counter-abuse-alerts@google.com The total number of enabled extensions that are not present in the Enhanced Safe Browsing CRX allowlist. Recorded for "user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) on profile initialization. jeffcyr@google.com chrome-counter-abuse-alerts@google.com The total number of enabled extensions that are not present in the Enhanced Safe Browsing CRX allowlist. Recorded for only for Enhanced Safe Browsing users on "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. rdevlin.cronin@chromium.org extensions-core@chromium.org The permissions present in an extension when it was installed. To find places where this histogram may be emitted, look for calls to InstalledLoader::RecordPermissionMessagesHistogram with the argument Install. Emitted once per "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. For Sync users, this is reported for each device. rdevlin.cronin@chromium.org extensions-core@chromium.org The permissions present in an extension when it was loaded (which happens at profile open or extension install). Only emitted for quot;user profiles" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed). To find places where this histogram may be emitted, look for calls to InstalledLoader::RecordPermissionMessagesHistogram with the argument Load. nmuggli@google.com msisov@igalia.com Records whether users of the chrome.printing extension API are using margins values that are supported by the printer. nmuggli@google.com msisov@igalia.com Records whether users of the chrome.printing extension API are using print scaling values that are supported by the printer. rdevlin.cronin@chromium.org extensions-core@chromium.org Whether an extension had host permissions withheld as a result of the RuntimeHostPermissions feature. Recorded once per extension at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization if and only if the RuntimeHostPermissions feature is enabled and the extension requests any host permissions (i.e., could be affected by the feature). rdevlin.cronin@chromium.org extensions-core@chromium.org The number of hosts an extension has been granted explicit access to that it also requested (note that if the user granted unrequested hosts, those will not be included in this count). Recorded once per extension at "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization if and only if the RuntimeHostPermissions feature is enabled and the extension has had host permissions withheld. See also Extensions.RuntimeHostPermissions.ExtensionHasWithheldHosts. rdevlin.cronin@chromium.org bershanskyi@gmail.com extensions-core@chromium.org The number of extensions which have uninstall URL with given security properties: HTTPS protocol, HTTP protocol and local hostname, or HTTP protocol and non-local hostname. This histogram may allow us to deprecate support for insecure remote unistall URLs. For purposes of this histogram, any non-local domain name is considered non-local even if it resolves to a local IP. Recorded on extension load if an extension has a valid uninstall URL set. thefrog@chromium.org chrome-counter-abuse-alerts@google.com The number of blocklisted extensions found during a Safe Browsing extension check. Recorded each time a Safe Browsing check for extension IDs completes, whether synchronously or asynchronously. rdevlin.cronin@chromium.org extensions-core@chromium.org The reason an extension failed to unpack, recorded when a failure occurs. Replaced Extensions.SandboxUnpackFailureReason because the enum values were not in sync with the C++ enums. jlulejian@chromium.org extensions-core@chromium.org Records the reason an extension failed to unpack during an update. Emits when a failure occurs. rdevlin.cronin@chromium.org extensions-core@chromium.org Count the number of times a sandboxed CRX unpack succeeds. jlulejian@chromium.org extensions-core@chromium.org Records whether a sandboxed CRX unpack succeeds or fails during an update. Emits when the installation completes (either successfully or with a sandboxed unpacker failure). rdevlin.cronin@chromium.org kelvinjiang@chromium.org The number of enabled extensions with a search engine override specified in their manifest. Recorded once per "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) at profile initialization. jlulejian@chromium.org extensions-core@chromium.org It is emitted every time we add a pending task for a worker. Records true if the worker was ready to run tasks when pendings tasks are added (this is not optimal). Records false if the worker was not ready to run tasks when the pending task was added (this is the optimal expected state). `false` is recorded if the task is added when the extension is unloaded. Note: this histogram was incremented May, 2024 since it additionally started emmitting when the extension is unloaded. jlulejian@chromium.org extensions-core@chromium.org Tracks the result (ServiceWorkerExternalRequestResult) of when we attempt to remove (finish) an external request for the extension service worker. Emitted when we attempt to finish the external request after the browser has received an ack from the renderer that it fired the event in the service worker. jlulejian@chromium.org extensions-core@chromium.org Tracks the result (ServiceWorkerExternalRequestResult) of when we attempt to remove (finish) an external request for the extension service worker. Emitted when we attempt to finish the external request after the browser has received an ack from the renderer that it fired the event in the service worker. Specifically the emit is delayed until *after* we've attempted to return early for either a stopped worker or the starting of the external request failing. andreaorru@chromium.org jlulejian@chromium.org extensions-core@chromium.org When Extensions.ServiceWorkerBackground.WorkerCountAfterAdd == 2, this emits whether the previous and new worker added to WorkerIdSet had the same service worker version id. Warning: this histogram was expired from 2025-02-24 to 2025-08-15; data may be missing. andreaorru@chromium.org jlulejian@chromium.org extensions-core@chromium.org The content::ServiceWorkerRunningInfo::ServiceWorkerVersionStatus for the {WorkerType} WorkerIdSet. Only emitted when Extensions.ServiceWorkerBackground.WorkerCountAfterAdd == 2. This ensures there will be a new and previous worker to emit for. Warning: this histogram was expired from 2025-02-24 to 2025-08-15; data may be missing. jlulejian@chromium.org extensions-core@chromium.org Tracks when a background service worker fails to register what is the ServiceWorkerStatusCode that occurred. Logged each time a service worker fails to register. Some failures are expected and are not counted by this metric. jlulejian@chromium.org extensions-core@chromium.org Recorded when Service Worker registration wasn't found for an existing extension when attempting to verify that persisted-to-prefs (ExtensionPrefs) worker registration. It records the manifest location of the extension. Note: this histogram expired between 2023-04 and 2024-04, it will be missing data between those dates. jlulejian@chromium.org extensions-core@chromium.org Whether the attempt to re-register an extension Service Worker to mitigate missing registration issue succeeded. The attempt is performed during extension load. Note: incremented Aug, 2024 due to the implementation of worker registration retries which could increase the number of emits of this metric. jlulejian@chromium.org extensions-core@chromium.org When a mitigation for a mismatched registration state between ExtensionPrefs and the content service worker layer fails, this records the status that was returned by the content service worker layer for the registration request failure. Emitted when Extensions.ServiceWorkerBackground.RegistrationMismatchMitigated is false. jlulejian@chromium.org extensions-core@chromium.org The amount of time it takes to register a service worker background script with the content service worker layer. Measured in milliseconds from 1ms up to 10 seconds. jlulejian@chromium.org extensions-core@chromium.org Whether or not a Service Worker registration was found in the content service worker layer after finding a registration for the worker in ExtensionPrefs. Emitted immediately after the content service worker layer has tried to search for the registration. jlulejian@chromium.org extensions-core@chromium.org When we're about to request a worker to start to run an event/task this is emitted to indicate if the start was unneeded/redundant. Emitted just before we know that we are going to attempt to start a worker. A `true` value means that we will redundantly reqeust to start a worker when it was already running and could've processed the event without the request to start. A `false` value means that we correctly started the worker because it was not ready to run events. `false` is recorded if the worker start is requested when the extension is unloaded. Note: this histogram was incremented May, 2024 since it additionally started emmitting when the extension is unloaded. jlulejian@chromium.org extensions-core@chromium.org Tracks the result (ServiceWorkerExternalRequestResult) of when we attempt to add (start) an external request for the extension service worker. Logged each time an external request is added prior to dispatching the event to the service worker. jlulejian@chromium.org extensions-core@chromium.org Tracks when a background service worker fails to start what is the ServiceWorkerStatusCode that occurred. Logged each time a service worker fails to start when we attempt to start it for extension tasks. andreaorru@chromium.org extensions-core@chromium.org When starting a service worker fails due to a transient error, we retry multiple times to try to make the start succeed. Emits true if the retry results in a successful start. Emits false if either all retry attempts have been exhausted without success or a retry resulted in a non-transient error. jlulejian@chromium.org extensions-core@chromium.org Tracks whether background service worker starting succeeded or not. Logged each time a service worker has been started for extension tasks. jlulejian@chromium.org extensions-core@chromium.org The amount of time it takes to start the background service worker of an extension that succeeded in starting. Logged when we've confirmed the service worker is started for extension tasks to run. Warning: This histogram was expired from 2025-01-15 to 2025-04-03 data may be missing. jlulejian@chromium.org extensions-core@chromium.org The amount of time it takes to start the background service worker of an extension that failed in starting. Logged when we've confirmed the service worker has failed for extension tasks to run. Warning: This histogram was expired from 2024-11-13 to 2025-04-03 data may be missing. andreaorru@chromium.org jlulejian@chromium.org extensions-core@chromium.org The count of active workers registered in the extension ProcessManager for a given service worker-based extension. Reported immediately after a new worker is registered for the extension. andreaorru@chromium.org jlulejian@chromium.org extensions-core@chromium.org The count of active workers registered in the extension ProcessManager for a given service worker-based extension. Reported immediately after a worker for the extension is removed from the active set. Note: This histogram was expired between 2026-03 and 2026-06. jlulejian@chromium.org extensions-core@chromium.org When an extension requests that its service worker be registered with the content layer it can fail due to blink::ServiceWorkerStatusCode::kErrorTimeout. When this happens we retry multiple times to try to make the registration succeed. Emits true if the retry results in a successful registration. Emits false if either all retry attempts have been exhausted without success or a retry resulted in a status code that is not blink::ServiceWorkerStatusCode::kErrorTimeout. jlulejian@chromium.org extensions-core@chromium.org Tracks whether background service worker registration ultimately succeeded or unexpectedly not. It can be emitted whenever an extension is enabled (including updates). If there are attempts to retry registration, those are not emitted. See Extensions.ServiceWorkerBackground.WorkerRegistrationRetryAttemptsResult for a metric on retry attempts. jlulejian@chromium.org extensions-core@chromium.org Records the underlying net::Error that was encountered when the content service worker layer tries to fetch the worker script (from disk) but encounters a network error. It is emitted each time a worker script fetch fails for a blink::ServiceWorkerBackground::kErrorNetwork reason. jlulejian@chromium.org extensions-core@chromium.org The ServiceWorkerStatusCode when unregistering a worker for an extension fails unexpectedly. Emitted when Extensions.ServiceWorkerBackground.WorkerUnregistrationState is false. It is emitted when this failure happens in two scenarios when a worker may be unregistered: 1. due to an extension update to potentially unregister the old worker or 2. due to the extension being deactivated (due to disable, uninstall, or terminate) #1 and #2 can both occur for an extension update. #2 can occur independently outside of an extension update. {UnregistrationType} jlulejian@chromium.org extensions-core@chromium.org The success (true) or unexpected failure (false) of attempting to unregister a worker for an extension. This is emitted for two scenarios when a worker may be unregistered: 1. due to an extension update to potentially unregister the old worker or 2. due to the extension being deactivated (due to disable, uninstall, or terminate) #1 and #2 can both occur for an extension update. #2 can occur independently outside of an extension update. {UnregistrationType} andreaorru@chromium.org extensions-core@chromium.org Records whether a notification for a newly initialized service worker's version ID is older, equal to, or newer than the existing worker version ID. This metric is emitted during ServiceWorkerState::RendererDidInitializeServiceWorkerContext only when the renderer state is already "initialized" or "active" (i.e., not RendererState::kNotActive). jlulejian@chromium.org extensions-core@chromium.org This records the state of the extension loading in the (renderer) extension registry during the process of service worker script evaluation. Loaded means the extension is in the extension registry. Unloaded means the extension was loaded, but is now unloaded (disabled). Unknown means that there is no record of the extension in the renderer. It is emitted potentially after the worker thread is started and the worker script will soon or already is evaluating, but it is before the worker's extension bindings sytem is created. evasu@chromium.org extensions-core@chromium.org Logged once on profile initialization for non-incognito user profiles when the kExtensionsPinnedByDefault feature is enabled. Emits the boolean value of the kExtensionsPinnedByDefault preference, which tracks whether new extensions should be pinned to the toolbar by default. evasu@chromium.org extensions-core@chromium.org Emitted whenever the user changes the state of the "Pin new extensions" toggle on chrome://extensions. Records the new boolean value of the preference. rdevlin.cronin@chromium.org extensions-core@chromium.org top-chrome-desktop-ui@google.com The action taken on the settings overridden dialog that was shown to alert the user of an extension overriding the New Tab Page, when the dialog shown is the version that asks the user if they want to go back to Google's New Tab Page. Recorded once per instance of the dialog being shown, after the action is taken. rdevlin.cronin@chromium.org extensions-core@chromium.org top-chrome-desktop-ui@google.com The action taken on the settings overridden dialog that was shown to alert the user of an extension overriding the default search provider, when the dialog shown is the version that asks the user if they want to go back to Google search. Recorded once per instance of the dialog being shown, after the action is taken. rdevlin.cronin@chromium.org extensions-core@chromium.org top-chrome-desktop-ui@google.com The action taken on the settings overridden dialog that was shown to alert the user of an extension overriding the default search provider, when the dialog shown is the version that asks the user if they want to go back to a previous search engine that isn't Google. Recorded once per instance of the dialog being shown, after the action is taken. rdevlin.cronin@chromium.org extensions-core@chromium.org top-chrome-desktop-ui@google.com The action taken on the settings overridden dialog that was shown to alert the user of an extension overriding the New Tab Page, when the dialog shown is the generic version. Recorded once per instance of the dialog being shown, after the action is taken. rdevlin.cronin@chromium.org extensions-core@chromium.org top-chrome-desktop-ui@google.com The action taken on the settings overridden dialog that was shown to alert the user of an extension overriding the default search provider, when the dialog shown is the generic version. Recorded once per instance of the dialog being shown, after the action is taken. rdevlin.cronin@chromium.org extensions-core@chromium.org top-chrome-desktop-ui@google.com Records whether any search parameters are missing when populating the values for the Explicit Choice dialog. yeroshkin@google.com top-chrome-desktop-ui@google.com Recorded on browser window initialization on Windows and Mac. Records true if an installed extension controls the Default Search Engine (DSE), the extension's search engine matches the user's existing engine, and the user has not acknowledged the settings bubble (ack_settings_bubble). This detects the impacted state associated with crbug.com/540532980. evasu@chromium.org extensions-core@chromium.org Recorded on profile initialization for each extension that was originally pinned by default on installation. Logs whether the extension is currently pinned or unpinned by the user. Recorded only when the kExtensionsPinnedByDefault feature is enabled. nafisabedin@google.com clank-performance-team@google.com Tracks the Browser UI thread execution time of StorageFrontend::OnSettingsChanged when preparing and dispatching chrome.storage change events to extensions with active listeners. Recorded for each storage change notification that has at least one registered listener. alancutter@chromium.org extensions-core@chromium.org Records true whenever an extension sync install attempt was blocked because it was a default Chrome app that has been migrated over to a web app. Never records false. Warning: This histogram was expired from 2023-08-08 to 2023-10-16; data may be missing. quarz@chromium.org extensions-core@chromium.org Tracks Tabs API remove actions. quarz@chromium.org extensions-core@chromium.org Tracks Tabs API update actions. rdevlin.cronin@chromium.org extensions-core@chromium.org The total number of extensions that have an icon in the extension toolbar, including those that are unpinned and only show in the extensions menu. Measured once per "user" profile (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) open. Note: There was a typo in the name in the XML for this histogram until 2026-06, which may result in missing data on some platforms. evasu@chromium.org extensions-core@chromium.org The number of extensions in the request access button that were granted site access after the user clicked on the request access button. rdevlin.cronin@chromium.org extensions-core@chromium.org The source that triggered an extension action. Recorded once per invocation of an extension action. rdevlin.cronin@chromium.org extensions-core@chromium.org The number of extensions that the user has pinned on the toolbar. Recorded once per profile during initialization if the user has at least one extension with an action in the toolbar. rdevlin.cronin@chromium.org extensions-core@chromium.org The percentage of extensions that the user has pinned to the toolbar (i.e., this will be 100 if the user has every extension pinned). Recorded once per profile during initialization if the user has at least one extension with an action in the toolbar. evasu@chromium.org extensions-core@chromium.org The time elapsed between a user installing an extension and the first time the user clicks on that extension in ms. Recorded once per extension. rdevlin.cronin@chromium.org extensions-core@chromium.org The source for the extension uninstall. This is only recorded if an uninstall dialog is shown to the user (i.e., it is not recorded for internal "cleanups"). Note: this is no longer emitted for web app uninstalls as of M113. rdevlin.cronin@chromium.org extensions-core@chromium.org Uninstalls grouped by Extension::HistogramType. kelvinjiang@chromium.org extensions-core@chromium.org Logged when the user interacts with the dialog which uploads a local extension to their signed in account from the {Page} in chrome://extensions. Logs if the user proceeds with or cancels the extension upload. solomonkinard@chromium.org extensions-core@chromium.org Emitted each time a cross-origin extension navigation request occurs. Counts whether or not the target URL is a web accessible resource. It's possible that the upstream origin and target are different but both for the same extension (i.e. one for a static URL and the other for its dynamic URL). rdevlin.cronin@chromium.org src/extensions/OWNERS The total amount of time taken to evaluate declarativeNetRequest rules in the onBeforeRequest stage, measured in milliseconds. Recorded once per request if and only if at least one declarativeNetRequest rule is present. rdevlin.cronin@chromium.org src/extensions/OWNERS The total amount of time taken to evaluate declarativeNetRequest rules in the onBeforeRequest stage, measured in microseconds. Recorded once per request if and only if at least one declarativeNetRequest rule is present. This is only emitted for users with high resolution clocks. toyoshim@chromium.org chrome-loading@google.com Records the number of installed Extensions that require the Declarative{Web|Net}Request or their variant permission. The number will be clamped to 10 at maximum. This is recorded whenever a URLLoaderFactory is created for renderers. The metric is used for identifying the major reason to decide using the Extensions' loader proxy. We will consider possible optimization opportunities to reduce loading overheads. rdevlin.cronin@chromium.org src/extensions/OWNERS Records any flags that were registered in the extraInfoSpec of a webRequest listener, as well as the total number of listeners registered. Recorded each time a new listener is registered. toyoshim@chromium.org chrome-loading@google.com Records the decision of whether to proxy the request for the WebRequest API. This is recorded whenever a URLLoaderFactory is created for renderers. Warning: this histogram was expired from 2025-12-01 to 2026-01-06; data may be missing. toyoshim@chromium.org chrome-loading@google.com Records the reason of kWillProxyForExtension in the ProxyDecision2. This is recorded if and only if the reason is kWillProxyForExtension when a URLLoaderFactory is created for renderers. rdevlin.cronin@chromium.org src/extensions/OWNERS Records the request header added by extensions using the WebRequest API. Recorded for each network request during the OnBeforeSendHeaders stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org src/extensions/OWNERS Records the request header modified by extensions using the WebRequest API. Recorded for each network request during the OnBeforeSendHeaders stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org src/extensions/OWNERS Records the request header removed by extensions using the WebRequest API. Recorded for each network request during the OnBeforeSendHeaders stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org src/extensions/OWNERS Records the response header added by extensions using the WebRequest API. This is logged for the cumulative delta across all the web request extensions. Recorded for each network request during the OnHeadersReceived stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org src/extensions/OWNERS Records the response header modified by extensions using the WebRequest API. This is logged for the cumulative delta across all the web request extensions. Recorded for each network request during the OnHeadersReceived stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org src/extensions/OWNERS Records the response header removed by extensions using the WebRequest API. This is logged for the cumulative delta across all the web request extensions. Recorded for each network request during the OnHeadersReceived stage. Multiple samples can be recorded per request. rdevlin.cronin@chromium.org src/extensions/OWNERS The total time a network request took when at least one Web Request listener was registered at the start of the request, and a listener was blocked on the request. Measures from onBeforeRequest to onCompleted/onErrorOccurred, and does not include canceled or redirected requests. rdevlin.cronin@chromium.org src/extensions/OWNERS The total time a network request took when at least one Web Request listener with 'extraHeaders' in the extraInfoSpec was registered at the start of the request. Measures from onBeforeRequest to onCompleted/onErrorOccurred, and does not include canceled or redirected requests. rdevlin.cronin@chromium.org src/extensions/OWNERS The total time a network request took when at least one Web Request listener was registered at the start of the request. Measures from onBeforeRequest to onCompleted/onErrorOccurred, and does not include canceled or redirected requests. toyoshim@chromium.org chrome-loading@google.com Records the number of installed Extensions that require the WebRequest or its variant permission. The number will be clamped to 10 at maximum. This is recorded whenever a URLLoaderFactory is created for renderers. The metric is used for identifying the major reason to decide using the Extensions' loader proxy. We will consider possible optimization opportunities to reduce loading overheads. toyoshim@chromium.org chrome-loading@google.com Records the number of installed Extensions that require the WebView permission. The number will be clamped to 10 at maximum. This is recorded whenever a URLLoaderFactory is created for renderers. The metric is used for identifying the major reason to decide using the Extensions' loader proxy. We will consider possible optimization opportunities to reduce loading overheads. rdevlin.cronin@chromium.org src/extensions/OWNERS Counts the number of times an action is requested by extensions as part of the Web Request API. For a given web request stage, multiple actions may be logged. rdevlin.cronin@chromium.org extensions-core@chromium.org Number of enabled extensions which have requested the "webRequestBlocking" permission. Includes all kinds of extensions, including component and unpacked extensions. Recorded during "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. rdevlin.cronin@chromium.org extensions-core@chromium.org Number of enabled extensions which have requested the "webRequest" permission. Includes all kinds of extensions, including component and unpacked extensions. Recorded during "user profile" (profiles where people can install extensions, specifically profiles that can have non-component extensions installed) initialization. jeffcyr@google.com chrome-counter-abuse-alerts@google.com Reports the Safe Browsing CRX allowlist state received from Chrome Web Store when a user presses on "Add to Chrome" in Chrome Web Store. Warning: this histogram was expired from 2024-02-04 to 2025-01-07; data may be missing. jeffcyr@google.com chrome-counter-abuse-alerts@google.com Reports when a user with install friction dialog enabled tries to install an extension that is not included in the Safe Browsing CRX allowlist. 'True' if the install dialog is accepted or 'False' if the friction dialog or install dialog is canceled. Warning: this histogram was expired from 2024-04-28 to 2025-01-07; data may be missing. jeffcyr@google.com chrome-counter-abuse-alerts@google.com Reports when a user with install friction dialog disabled tries to install an extension that is not included in the Safe Browsing CRX allowlist. 'True' if the install dialog is accepted or 'False' if the install dialog is canceled. Warning: this histogram was expired from 2024-04-28 to 2025-01-07; data may be missing. uwyiming@chromium.org cws-consumer-team@google.com Records that the users clicked a link or button in the Extension Zero State promo page. The value indicates the link that the user clicked. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The detailed reason why enterprise policy forced extensions had failed to install because fetched update manifest was invalid. Recorded for each forced extension that failed to install after 5 minutes with Extensions.ForceInstalledFailureReason2 equal to MANIFEST_INVALID. Replaced Extensions.ForceInstalledFailureManifestInvalidErrorDetail due to addition of new error BAD_APP_STATUS, and some of the errors that were MISSING_UPDATE_CHECK_TAG would now be reported as BAD_APP_STATUS. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com The reason why enterprise policy forced extensions were not installed {ExtensionSource}. Recorded for each forced extension that failed to install after 5 minutes. Recorded together with "Extensions.ForceInstalledTimedOutCount" histogram, but for every extension not installed at the moment. Replaced Extensions.ForceInstalledFailureReason2 because of reporting MANIFEST_INVALID instead of MANIFEST_FETCH_FAILED in case parsing update manifest failed with different reasons for the extensions. giovax@google.com chromeos-commercial-chrome-apps-and-extensions@google.com managed-devices@google.com HTTP error code for the last retry attempt when for enterprise policy forced extensions failed with {ErrorType}. Recorded for each forced extension that failed to install after 5 minutes with Extensions.`OffStore,WebStore`_ForceInstalledFailureReason3 equal to {ErrorType} and a HTTP response code was received. HTTP response code is received only if there was no network error. Replaced Extensions.ForceInstalledHttpErrorCode because error codes are now reported only when network error code is HTTP_RESPONSE_CODE_FAILURE. anunoy@chromium.org chrome-counter-abuse-alerts@google.com Reports the status (Enabled or Disabled) of policy-installed extensions that perform a {OverrideType} on {TrustLevel} devices where the extension is {InstallMode}. Logged once at startup during ExtensionService initialization. Note: This is only recorded on Windows and Mac. This is only emitted for regular user profiles, and is skipped for guest and incognito profiles. mcnee@chromium.org wjmaclean@chromium.org src/components/guest_view/OWNERS Indicates the type of guest view created. Emitted once per guest view object.