mschillaci@google.com aldietz@google.com dtseng@google.com chrome-a11y-core@google.com Tracks the amount of time (in ms) that the accessibility engine was {CurrentState} before {CallType}. This is recorded either at the start of the onDisabled callback, or immediately before the call to reEnableRendererAccessibility. mschillaci@google.com aldietz@google.com dtseng@google.com chrome-a11y-core@google.com Tracks when the Auto-disable Accessibility feature changes the state of the accessibility engine by calling {MethodCall}. This is {CallType}. aaronmoss@google.com chrome-a11y-core@google.com Tracks the maximum number of AccessibilityNodeInfo objects that were stored in the Java-side cache during a single session. aaronmoss@google.com chrome-a11y-core@google.com Tracks the percentage of calls from the Android framework serviced from cache during a single session where the cached AccessibilityNodeInfo object was still fresh. Only produced in the AccessibilityCheckJavaNodeCacheFreshness experiment. aaronmoss@google.com chrome-a11y-core@google.com Tracks the percentage of calls from the Android framework to create a new AccessibilityNodeInfo object that were serviced from the cache rather than constructing the object from scratch during a single session. lokeric@google.com mschillaci@google.com chrome-a11y-core@google.com Tracks whether caret browsing is enabled at startup. lokeric@google.com mschillaci@google.com chrome-a11y-core@google.com Tracks users' actions for turning on/off caret browsing. gmarcoesau@google.com chrome-a11y-core@google.com Will count the amount of times we call an event with either CONTENT_CHANGE_TYPE_SUBTREE being true or false. This will be called everytime an event of this type is fired. mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@chromium.org Tracks the type of element that a user navigates by in the web contents when the Android Framework calls performAction with the ACTION_NEXT_HTML_ELEMENT action. This is tracked during the tree search for the next/previous element. This occured with: {RunningATs} mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@chromium.org Tracks the combinations of mode flags that are set when there is a request to load inline text boxes on Android. This occurs when {CallLocation}. mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@chromium.org Tracks if the inline text boxes for a node have already been requested and generated when an AT calls the addExtraDataToAccessibilityNodeInfo method to explicitly request that we add the boxes for that node. mschillaci@google.com katie@chromium.org jhimawan@google.com hitarthkothari@google.com chrome-a11y-core@google.com When a keyboard shortcut is used on Android, tracks the action of the shortcut, and splits based on whether or not a screen reader is running. mschillaci@google.com abigailbklein@google.com chrome-a11y-core@google.com Tracks the number of AccessibilityEvents dropped when the OnDemand accessibility services feature is enabled. Recorded at the end of a session. mschillaci@google.com abigailbklein@google.com chrome-a11y-core@google.com Tracks the number of AccessibilityEvents dropped when the OnDemand accessibility services feature is enabled, and when the total percentage of dropped events is 100%. Recorded at the end of a session. mschillaci@google.com abigailbklein@google.com chrome-a11y-core@google.com Tracks the number of AccessibilityEvents dropped when the OnDemand accessibility services feature is enabled, and the AccessibilityPerformanceFiltering feature is enabled, and the number of events dropped is 100%. Tracks for when the AXMode is set to {AXMode}. Recorded at the end of a session. Updated in M114 to add FormControls variant. mschillaci@google.com abigailbklein@google.com chrome-a11y-core@google.com Tracks the percentage of AccessibilityEvents dropped when the OnDemand accessibility services feature is enabled. Recorded at the end of a session. mschillaci@google.com abigailbklein@google.com chrome-a11y-core@google.com Tracks the percentage of AccessibilityEvents dropped when the OnDemand accessibility services feature is enabled, and the AccessibilityPerformanceFiltering feature is enabled. Tracks for when the AXMode is set to {AXMode}. Recorded at the end of a session. Updated in M114 to add FormControls variant. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com Tracks the enabled state for the Page Zoom option on the main app menu. The state will be one of the following enumerated states: 0) not enabled, 1) enabled explicitly by the user on the Accessibility Page Zoom setting, 2) enabled automatically if the user has an Android OS-wide default font size, 3) disabled explicitly by the user on the Accessibility Page Zoom setting. 4) enabled by default for large form factor users. Recorded each time the app menu is opened. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com Tracks whether the user opened the Page Zoom slider from the app menu option. Recorded each time the slider is opened from the app menu. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com Tracks whether the user changed the individual page zoom level on at least one webpage from the app menu slider view. Recorded each time the slider is dismissed if the user changed the zoom level before dismissal. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com For users who changed the individual page zoom level on at least one webpage from the app menu slider view, tracks what zoom level has been set on the page. Recorded each time the slider is dismissed if the user changed the zoom level before dismissal. mschillaci@google.com chrome-a11y-core@google.com Tracks the zoom factor when visual properties of the main frame are updated. This will be recorded each time the properties change. The value can be recorded multiple times for a single frame, for example as a user is changing zoom value with the slider on Android. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com Tracks whether the user changed the default page zoom level from the Accessibility Page Zoom settings page. Recorded each time the user closes the Accessibility Page Zoom settings page if the user changed the zoom level while the settings page was showing. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com For users who changed the default page zoom level from the Accessibility Page Zoom settings page, tracks what default zoom level has been set in the settings. Recorded each time the user closes the Accessibility Page Zoom settings page if the user changed the zoom level while the settings page was showing. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com Tracks what type of user the current user is considered for the Accessibility Page Zoom feature. The user can be in one of four buckets: a user that has saved a custom zoom level on at least one site; a user that has a default zoom level choice for all sites; a user that has both; a user that has none. Any of the former three is considered an active user of the feature. This is tracked once on browser start up. Note: Users can move between these groups, although they can only be in one group at a time. mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@google.com Tracks the total amount of time that an instance of WebContentsAccessibilityImpl spends in the createAccessibilityNodeInfo method. This timing only begins after the native code is initialized, which happens when an AT interacts with the Android framework while Chrome is open, and tracks the net time until the WebContentsAccessibilityImpl instance for this tab is destroyed. The metric is recorded when the WebContentsAccessibilityImpl object loses foreground focus (e.g. switching tabs, closing tabs, sending Chrome to the background, etc). gmarcoesau@google.com chrome-a11y-core@google.com Tracks how long (in milliseconds) a node lived in the fake Android cache. Recorded when a node is removed or cleared from the fake cache. gmarcoesau@google.com chrome-a11y-core@google.com Tracks the size of the fake Android cache. gmarcoesau@google.com chrome-a11y-core@google.com {Metric} which will be recorded every time a validation is performed on the fake cache. rickyyang@google.com lucasradaelli@google.com chrome-a11y-core@google.com Tracks the time it takes for a single one-shot tree search to find an element. This is done during the WebContentsAccessibilityAndroid#FindElementType method, which searches for the next element in a tree for a move by granularity action. We only track this for a completed tree search (i.e. one that finds a node successfully), ignoring early-exits, to get an upper bound on the method cost. This metric has a range of 1 to 1000 microseconds. UMA data analysis confirmed this range is appropriate. Note: This metric is only recorded on devices with high-resolution clocks. mschillaci@google.com chrome-a11y-core@google.com Tracks the time it takes to computeText, i.e. create Spannables, for a single AccessibilityNodeInfo on Android. This is used to track potential performance impact of the AccessibilityTextFormatting feature and is meant to be temporary. The histogram is recorded immediately before the constructed Spannable is set on the node. Note: This metric is only recorded on devices with high-resolution clocks. dtseng@chromium.org chrome-a11y-core@google.com Tracks the time it takes to request a scroll to make visible action and receive a reply in the form of a scroll position change. mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@google.com Tracks the time it takes for the WebContentsAccessibilityImpl to start native initialization, until a node on the page is given accessibility focus for the first time. We restrict this to TalkBack, which we know always focuses the first item on a page. The metric is recorded when the AccessibilityEvent is dispatched to the view. aaronmoss@google.com davidsegovia@google.com chrome-a11y-core@google.com Logged during browser startup and accessibility tool activation when the provided tool is enabled. aluh@chromium.org chrome-a11y-core@google.com The total amount of time taken to populate the AccessibilityNodeInfo text with {Bucket} text formatting style ranges in Clank with the AccessibilityTextFormatting feature enabled. aluh@chromium.org chrome-a11y-core@google.com The amount of time taken to perform the {Operation} operation {WithStyleData} when populating the AccessibilityNodeInfo text in Clank with the AccessibilityTextFormatting feature enabled. aluh@chromium.org chrome-a11y-core@google.com The number of text formatting style ranges when populating the AccessibilityNodeInfo text with {Bucket} characters in Clank with the AccessibilityTextFormatting feature enabled. aluh@chromium.org chrome-a11y-core@google.com The total number of text formatting style ranges when populating the AccessibilityNodeInfo text in Clank with the AccessibilityTextFormatting feature enabled. aluh@chromium.org chrome-a11y-core@google.com The length of text {WithStyleData} when populating the AccessibilityNodeInfo text in Clank with the AccessibilityTextFormatting feature enabled. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com Recorded every time the AccessibilityState.updateAccessibilityServices method hit the criteria to poll. Lower number of hits is better. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com Tracks the number of times this sequence of calls to AccessibilityState.updateAccessibilityServices required polling to get consistent enabled and running services. Lower count is better. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com Tracks the number of times the AccessibilityState.updateAccessibilityServices did not complete polling before the max timeout. This should be rare. Any instances of this are bad. Lower number of hits is better, should (almost always) be zero. mschillaci@google.com aldietz@google.com chrome-a11y-core@google.com Tracks the amount of time the AccessibilityState.updateAccessibilityServices method took from start to finish (not counting async wait time). Lower time is better. mschillaci@google.com chrome-a11y-core@google.com Tracks the total amount of time that this WebContents spent in the foreground for usages with the native accessibility engine always initialized. That is, this is a measure of time spent on the web for users that always have an accessibility service running. Recorded when an instance is hidden per WebContentsObserver#wasHidden (e.g. backgrounded Chrome, opened a new Tab, went to Settings etc), and is equal to the time since the last call to WebContentsObserver#wasShown. This can be recorded multiple times for a single WebContents. mschillaci@google.com chrome-a11y-core@google.com Tracks the total amount of time that this WebContents spent {UsageType}. Recorded when an instance is hidden per WebContentsObserver#wasHidden (e.g. backgrounded Chrome, opened a new Tab, went to Settings etc), and is equal to the time since the last call to WebContentsObserver#wasShown. This can be recorded multiple times for a single WebContents. aaronmoss@google.com aldietz@google.com dtseng@chromium.org chrome-a11y-core@google.com Tracks events, flags, feedback and capabilities of enabled accessibility services separated into variants based on the types of running accessibility services. It allows us to track requested flags, capabilities, and events, segmented by which type of accessibility services the user has active. It replaces the equivalent Accessibility.AndroidServiceInfo.{RunningApps} histogram due to a time-series break where all services with the Android S+ isAccessibilityTool flag are classified as ASSISTIVE_TECH. jdiggs@chromium.org jkim@igalia.com chrome-a11y-core@google.com Tracks usage of ATK APIs on Linux Desktop. Recorded when ATK APIs that are supposed to trigger AX mode enabled is called. dtseng@chromium.org chrome-a11y-core@google.com Time spent evaluating the AXEmptyGroup mac subrole predicate (-subrole on NSAccessibilityGroupRole) per top-level call on macOS. Escalate to eager build-time compute if p99 exceeds 100 microseconds on representative pages during normal VoiceOver linear navigation. This histogram is recorded via base::UmaHistogramMicrosecondsTimes, so it is only reported for clients with high-resolution clocks. mschillaci@google.com zork@google.com nektar@chromium.org chrome-a11y-core@google.com This histogram measures the amount of times that the ScreenAI service disconnects {DisconnectCount} from the AXTreeFixing service after it had previously been initialized and connected. mschillaci@google.com zork@google.com nektar@chromium.org chrome-a11y-core@google.com This histogram measures whether or not a main node was identified after the AXTreeFixing service made a request to the ScreenAI service and successfully received a response from the service. mschillaci@google.com zork@google.com nektar@chromium.org chrome-a11y-core@google.com This histogram measures the amount of times that the AXTreeFixing service attempts to initialize the ScreenAI service. mschillaci@google.com zork@google.com nektar@chromium.org chrome-a11y-core@google.com This histogram measures the amount of times that the AXTreeFixing service failed to initialize the ScreenAI service after 3 failed attempts. mschillaci@google.com zork@google.com nektar@chromium.org chrome-a11y-core@google.com This histogram measures the amount of times that it took for the ScreenAI service to successfully initialize for the AXTreeFixing service. A value of 1 means that it initialized on the first try (happy-path). We attempt to initialize 3 times before stopping. mschillaci@google.com zork@google.com nektar@chromium.org chrome-a11y-core@google.com This histogram records the type of request that clients made to the AXTreeFixing service for ScreenAI specifically for main node identification. Requests can come before initialization, or with an invalid tree that already contains a main node, etc. mschillaci@google.com zork@google.com nektar@chromium.org chrome-a11y-core@google.com This histogram measures the total time (in ms) that a request for main node identification from the AXTreeFixing service to the ScreenAI service took to complete. mschillaci@google.com zork@google.com nektar@chromium.org chrome-a11y-core@google.com This histogram records the number of times that the AXTreeFixing service {RequestResponseType} to identify the main node of a tree. mschillaci@google.com zork@google.com nektar@chromium.org chrome-a11y-core@google.com This histogram measures the initial Role of an identified main node after the AXTreeFixing service made a request to the ScreenAI service for main node identification. mschillaci@google.com chrome-a11y-core@google.com The number of times that an AXTreeSnapshot request was not properly fulfilled, split by error reason. Each individual snapshot request can only report one failure reason. A page with multiple render frames can have some snapshots succeed, and others fail. On repeat calls for snapshots, a previously succeeding call may fail, or vice versa. mschillaci@google.com chrome-a11y-core@google.com The number of times that an AXTreeSnapshot has been requested by any client. Each request is per render frame, so this can be counted multiple times on a page, and a snapshot can be requested multiple times per page. kevers@chromium.org chrome-a11y-core@chromium.org Tracks when combinations of mode flags are set. Records when the mode flag changes and aligns with one of the common (named) flag bundles. rhalavati@google.com chrome-a11y-core@google.com Records the heuristic result determining whether an HTML canvas element has or needs accessibility support. Logged with a delay after the canvas accessibility manager changes the heuristic result or upon context destruction. This metric is recorded as a best effort and may not represent the final heuristic result if the canvas element is changed frequently, or may not get recorded at all if the browser is shut down too quickly after the last change. evliu@google.com chrome-media-ux@google.com Whether custom caption settings were loaded from the user preferences. Recorded when WebKit preferences are overridden. evliu@google.com chrome-media-ux@google.com Whether custom caption settings were loaded from the system preferences. Recorded when WebKit preferences are overridden. kyungjunlee@google.com chrome-a11y-core@google.com Records when a user performs a ChromeVox command. dtseng@chromium.org chrome-a11y-core@google.com A user can control ChromeVox via a variety of gestures on the touch screen. For example, swiping right with one finger causes ChromeVox to navigate to the next object. Track all possible gestures here. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. katie@chromium.org chrome-a11y-core@google.com The duration of time from when ChromeVox was first loaded to when the ChromeVox welcome message was spoken. katie@chromium.org dtseng@chromium.org chrome-a11y-core@google.com Recorded when a user has picked a new autoclick action type from the bubble menu. aluh@chromium.org chrome-a11y-core@google.com The bounce keys delay duration in milliseconds set by the user if Bounce Keys is turned on. Logged once per profile load (signin screen or user profile). katie@chromium.org chrome-a11y-core@google.com The caret blink interval rate, in milliseconds, chosen by the user, from 12 possible values in chrome os settings. 0ms means "do not blink", and the default value is 500ms. Logged once per profile load (signin screen or user profile). For how users adjust the setting from settings, see ChromeOS.Settings.Accessibility.CaretBlinkInterval, which logs each time the setting changes. katie@chromium.org chrome-a11y-core@google.com The color correction filter intensity chosen by the user. Logged once per profile load (signin screen or user profile). For how users adjust the setting from settings, see ChromeOS.Settings.Accessibility.ColorCorrection.FilterAmount, which logs each time the setting changes. katie@chromium.org chrome-a11y-core@google.com The color correction filter type chosen by the user. Logged once per profile load (signin screen or user profile). For how users adjust the setting from settings, see ChromeOS.Settings.Accessibility.ColorCorrection.FilterType, which logs each time the setting changes. katie@chromium.org chrome-a11y-core@google.com The color of the Chrome OS accessibility cursor. Note: This metric is logged once per profile load (signin screen or user profile). katie@chromium.org dtseng@chromium.org chrome-a11y-core@google.com The language used for speech recognition in dictation on ChromeOS. This is logged each time Dictation is toggled on. From M99 to M104 this was logged using base::PersistantHash instead of base::HashMetricName; data from that period can be decoded using a map between the two hashing functions. See crbug.com/1342966. katie@chromium.org chrome-a11y-core@google.com Duration that the network speech recognition service was listening for dictation. Recorded each time a user toggles dictation on until dictation is stopped, either by the user action, error, or timeout. katie@chromium.org chrome-a11y-core@google.com Duration that the on-device speech recognition service was listening for dictation. Recorded each time a user toggles dictation on until dictation is stopped, either by the user action, error, or timeout. katie@chromium.org chrome-a11y-core@google.com Recorded whenever Dictation fails to perform a macro. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. katie@chromium.org chrome-a11y-core@google.com Recorded whenever Dictation recognizes a macro. katie@chromium.org chrome-a11y-core@google.com Recorded whenever Dictation successfully performs a macro. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. katie@chromium.org chrome-a11y-core@google.com Records whether Pumpkin successfully parsed a command. This histogram is recorded each time Pumpkin is used to parse a command. anastasi@google.com dtseng@chromium.org chrome-a11y-core@google.com Records how users invoke Dictation. katie@chromium.org chrome-a11y-core@google.com When Dictation was toggled on, records whether on-device speech recognition was used. If on-device recognition was not used, network speech was used. katie@chromium.org chrome-a11y-core@google.com Records whether Pumpkin was used to parse a command. If Pumpkin was not used, then regex parsing was used. This histogram is recorded each time Dictation parses a command. lkupo@chromium.org chrome-a11y-core@google.com Whether the built-in touchpad is enabled or disabled. It logs when the touchpad is disabled, i.e. setting the internal touchpad mode to "Always disabled" or "Disabled on mouse connected", and when the touchpad is enabled, which occurs when the internal touchpad mode is set to "Never disabled". katie@chromium.org dtseng@chromium.org chrome-a11y-core@google.com Cursor size of the Chrome OS Large Cursor (logged once per profile load (signin screen or user profile)). This replaced Accessibility.CrosLargeCursorSize in M124. katie@chromium.org chrome-a11y-core@google.com Whether Select-to-Speak had background shading enabled when activated. anastasi@google.com katie@chromium.org chrome-a11y-core@google.com Records each action the user selects in the Select-to-Speak bubble. ajitnarayanan@google.com chrome-a11y-core@google.com When Select-to-speak is active, the user can dismiss the bubble menu in multiple ways: by clicking the cancel button on the Select-to-speak menu or using keyboard shortcuts. Track the methods here. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. ajitnarayanan@google.com chrome-a11y-core@google.com Whether enhanced network TTS voices were enabled when Select-to-Speak was activated. Enhanced network voices were forced off in M152. ajitnarayanan@google.com chrome-a11y-core@google.com Whether Select-to-Speak's navigation controls were on when activated. ajitnarayanan@google.com chrome-a11y-core@google.com The multiplier with which the user overrode the speech rate setting in Select-to-Speak. By default, the global Text-to-Speech setting is used, which the user can temporarily override. The override multiplier is stored as a sparse histogram with values (100 * multiple). For example, a speech rate multiplier of 1.0 (default) will be seen as 100. Emitted once every time playback starts, including on resume after pause or change of selection. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. ajitnarayanan@google.com chrome-a11y-core@google.com When Select-to-speak is active, the user can navigate between paragraphs in multiple ways: by clicking the navigation buttons on the Select-to-speak menu or using keyboard shortcuts. Track the methods here. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. ajitnarayanan@google.com chrome-a11y-core@google.com When Select-to-speak is active, the user can navigate between sentences in multiple ways: by clicking the navigation buttons on the Select-to-speak menu or using keyboard shortcuts. Track the methods here. anastasi@google.com katie@chromium.org chrome-a11y-core@google.com Records the duration that Select-to-Speak is continuously talking. This is recorded every time a new speech request is completed in Select-to-Speak, and does not reflect total talking time during a user session. anastasi@google.com katie@chromium.org chrome-a11y-core@google.com Records the speed the user selects from the Select-to-Speak speed bubble. katie@chromium.org chrome-a11y-core@google.com A user may activate Select-to-Speak by holding down 'search' and clicking or dragging a region with the mouse, or by highlighting an area and using search + s to read just the highlighted area. Track the methods here. katie@chromium.org chrome-a11y-core@google.com A user has tapped a button in the tray to change Select-to-Speak's state. The tap was interpreted by Select-to-Speak as a request to start selection, to cancel speech, or to cancel selection, depending on Select-to-Speak's internal state when the tap occured. This tracks when the button was tapped and the event that it generated. ajitnarayanan@google.com chrome-a11y-core@google.com Which TTS engine was used for making TTS requests from Select-to-speak. This is recorded every time a new speech request is made in Select-to-speak. Note that this is only recorded on the start of speech, so it is not recorded, for example, when the user resumes speech after pausing it. anastasi@google.com katie@chromium.org chrome-a11y-core@google.com Tracks how long the Select-to-Speak {BubbleType} bubble is displayed onscreen. aluh@chromium.org chrome-a11y-core@google.com The slow keys delay duration in milliseconds set by the user if Slow Keys is turned on. Logged once per profile load (signin screen or user profile). lucasradaelli@google.com chrome-a11y-core@google.com Tracks whether the Chrome OS Spoken Feedback feature is on. dtseng@chromium.org katie@chromium.org chrome-a11y-core@google.com Logged whenever the connection state of a braille display changes between disconnected and connected. dtseng@chromium.org katie@chromium.org chrome-a11y-core@google.com Records the duration of time that a single Braille display was connected. This starts when a Braille display connects at startup or due to user input, and may stop when the user ends their session by turning off the machine, or when they disconnect or turn off the Braille display. anastasi@google.com katie@chromium.org chrome-a11y-core@google.com Records when the ChromeOS feature, {FeatureName}, is toggled from the status area, also known as "Quick Settings". dtseng@chromium.org anastasi@google.com chrome-a11y-core@google.com The value of the Switch Access "Auto Scan" setting, logged immediately after toggling. This will show us how often users are turning the feature on, and how often they are turning it back off again. dtseng@chromium.org anastasi@google.com chrome-a11y-core@google.com Measures the user-set speed for scanning between keyboard keys in Switch Access, logged immediately after changing the setting. Values range from 1ms to 10000ms, in 100ms buckets. dtseng@chromium.org anastasi@google.com chrome-a11y-core@google.com Measures the user-set speed for auto scanning between items in Switch Access, logged immediately after changing the setting. Values range from 1ms to 10000ms, in 100ms buckets. dtseng@chromium.org anastasi@google.com chrome-a11y-core@google.com Switch Access error occurred. See CrosSwitchAccessError enum for error types. dtseng@chromium.org anastasi@google.com chrome-a11y-core@google.com Which key code user has assigned to the Next Action (e.g. 32 for the Space key) dtseng@chromium.org anastasi@google.com chrome-a11y-core@google.com Which key code user has assigned to the Previous Action (e.g. 32 for the Space key) dtseng@chromium.org anastasi@google.com chrome-a11y-core@google.com Which key code user has assigned to the Select Action (e.g. 32 for the Space key) katie@chromium.org chrome-a11y-core@google.com Records the duration of time that the {FeatureName} feature was enabled within a login session. This may start when the user logs in or when they enable the feature, and may stop when the user ends their session by logging out or turning off the machine, or when they disable the feature. dtseng@chromium.org katie@chromium.org chrome-a11y-core@google.com Note: This metric is logged once per profile load (signin screen or user profile). Whether the user has enabled the Chrome OS feature: {SettingType} xiangxiao@google.com chrome-a11y-core@google.com The time takes to load the file and create the TFLite dependency parser model. This histogram is recorded once for each successful creation of the model. xiangxiao@google.com chrome-a11y-core@google.com The state of the dependency parser model used by Reading Mode. Recorded once per model load attempt for each renderer process. xiangxiao@google.com chrome-a11y-core@google.com The time taken to prepare the input and run the TFLite dependency parser model. This histogram is recorded once for each invocation of the model. The model may be invoked multiple times after being loaded, running against a sequence of sentences. xiangxiao@google.com chrome-a11y-core@google.com The size of the input to the TFLite dependency parser model, in number of tokens. This histogram is recorded once for each invocation of the model. The model may be invoked multiple times after being loaded, running against a sequence of sentences. xiangxiao@google.com chrome-a11y-core@google.com Whether the dependency graph was successfully generated by the TFLite dependency parser model. This histogram is recorded once for each invocation of the model. The model may be invoked multiple times after being loaded, running against a sequence of sentences. xiangxiao@google.com chrome-a11y-core@google.com Records whether the dependency parser model file provided by the OptimizationGuide was valid and was successfully loaded by the DependencyParserModelLoader. Recorded once per model update by the OptimizationGuide. grt@chromium.org lucasradaelli@google.com Recorded each time accessibility for a single WebContents is disabled due to the ProgressiveAccessibility feature. katie@chromium.org chrome-a11y-core@google.com The FaceGaze assets DLC installation is triggered when one of the features using the DLC (currently the only feature using FaceGaze assets is FaceGaze) is enabled. This histogram records the time taken to successfully install the FaceGaze assets DLC. Note that this histogram is not recorded if the installation fails. katie@chromium.org chrome-a11y-core@google.com The FaceGaze assets DLC installation is triggered when one of the features using the DLC (currently the only feature using FaceGaze assets is FaceGaze) is enabled. This histogram is recorded once when FaceGaze assets installation finishes with either success or failure. katie@chromium.org chrome-a11y-core@google.com The Pumpkin DLC installation is triggered when one of the features using the DLC (currently the only feature using Pumpkin is Dictation) is enabled. This histogram records the time taken to successfully install the Pumpkin DLC. Note that this histogram is not recorded if the installation fails. mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@google.com This histogram tracks the number of page navigations from start-up until the kWebContents AXMode is first used, up until 10000. This is tracked only one per instance, and is recorded as the accessibility code is enable. mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@google.com This histogram tracks the time from start-up until the kWebContents AXMode is first used. This is tracked only one per instance, and is recorded as the accessibility code is enable. grt@chromium.org lucasradaelli@google.com The round-trip time to send a set of accessibility mode flags from the browser process to a renderer and receive and process the first set of updates and events. Recorded once each time the browser process receives the first set of updates and events from a renderer following {Variation} call to RenderAccessibility::SetMode. aldietz@google.com chrome-a11y-core@google.com Records whether the experimental form controls mode flag is set for the AXMode. Tracked when the experimental form controls mode flag is flipped to true. This flag is flipped automatically when software communicates with Chrome via accessibility APIs. As of M115, this flag should only be flipped on when the AccessibilityPerformanceFiltering feature is enabled. This is currently only used on Android OS. katie@chromium.org chrome-a11y-core@google.com The time it takes for the FaceLandmarker API to process a single video frame. This histogram is recorded once every 100 frames and represents the average latency of the FaceLandmarker API on those frames. The reason we use the average is because there could be potentially thousands of calls to the FaceLandmarker API during a FaceGaze session and we don't want to clutter the histograms. Each call to record a histogram also takes work and we don't want to spam the histograms API multiple times per second. lucasradaelli@google.com chrome-a11y-core@google.com The value of the "show a quick focus highlight" setting, logged immediately after toggling. This will show us how often users are turning the feature on, and how often they are turning it back off again. dtseng@chromium.org mschillaci@google.com chrome-a11y-core@google.com Whether the Chrome accessibility image label setting is on for Android. Logged when the profile opens via browser startup, and any time an image labelling setting changes. dtseng@chromium.org mschillaci@google.com chrome-a11y-core@google.com When a user opens the accessibility image label dialog on Android, records what option they select on user interaction. dtseng@chromium.org mschillaci@google.com chrome-a11y-core@google.com Whether the Chrome accessibility image label setting for Android is set to only be enabled on a Wi-Fi connection. Logged when the profile opens via browser startup, and any time an image labelling setting changes. katie@chromium.org dtseng@chromium.org Whether a user accepts or does not accept a modal dialog enabling the image labels option. If the user does not accept it this does not track whether they closed it with the negative button, the close button, or keyboard escape. katie@chromium.org dtseng@chromium.org chrome-a11y-core@google.com The language of a web page where image labels were requested, as detected by Chrome (not necessarily what language the page claims to be in). katie@chromium.org dtseng@chromium.org chrome-a11y-core@google.com The language that was requested for image descriptions, based on the page language, the user's accept languages and top languages, and the server languages. dtseng@chromium.org mschillaci@google.com chrome-a11y-core@google.com Counts the number of images that got a certain result from automatic image labeling (empty, error, or success), as a function of the function of one of the image's dimensions - either the min or the max dimension. Warning: this histogram was expired from 2026-02-01 to 2026-04-22, data might be missing. dtseng@chromium.org mschillaci@google.com chrome-a11y-core@google.com Counts the number of images that got a certain result from automatic image labeling (empty, error, or success), as a function of the function of the length of the characters in the image's name - either the original name, or the name after removing stopwords. katie@chromium.org chrome-a11y-core@google.com Whether the Chrome accessibility image label setting is on. Logged when the profile opens via browser startup, and any time an image labelling setting changes. Only logged for regular profiles, Incognito profiles, and guest off-the-record profiles, as these are the only profiles that can display web content. mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@chromium.org Tracks the number of nodes that have inline text boxes loaded per AXTreeUpdate, if any are present. We track this to get a sense of the number of nodes that we are loading text boxes for, since they have such a large performance cost. We track this while computing pending changes of an AXTreeUpdate in AXTree::Unserialize. mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@chromium.org Tracks whether or not a given AXTreeUpdate contains any inline text boxes. We track this while computing pending changes of an AXTreeUpdate in AXTree::Unserialize. gambard@chromium.org rkgibson@google.com This metric is related to the Preferred Content Size chosen by the user. It is only recorded once per session. This is hit if the chosen category is not listed in the map defined in /ios/components/ui_util/dynamic_type_util.mm. In that case, we should update the code by adding an entry for the new category in that map. This is logged when the helper to returning the multiplier associated with the current preferred content size is called. evliu@google.com chrome-media-ux@google.com Whether the sample rate or channel count of a Live Caption audio stream changed midstream. This is logged once per audio stream on the destruction of the Cloud speech recognition client. evliu@google.com chrome-media-ux@google.com Records when the caption bubble displays an error. This is logged once each time the caption bubble model encounters an error. evliu@google.com chrome-media-ux@google.com Measures how long SODA was running while the Live Caption UI was {Visibility}. Logged once on the destruction of the SpeechRecognitionRecognizerImpl. evliu@google.com chrome-media-ux@google.com Records when a user enables or disables the Live Caption feature from {Entrypoint}. evliu@google.com chrome-media-ux@google.com Records when a user expands or collapses the Live Caption bubble. evliu@google.com chrome-media-ux@google.com Whether the Live Caption feature flag is enabled. This is logged once when the Live Caption controller is initialized. evliu@google.com chrome-media-ux@google.com The number of languages used to initialize the Speech On-Device API (SODA). This is logged each time SODA is reset. evliu@google.com chrome-media-ux@google.com The error code of a failed attempt to load the Speech On-Device API (SODA) binary. This is logged once for each media stream if the SODA binary failed to load on Windows. evliu@google.com chrome-media-ux@google.com The result of an attempt to load the Speech On-Device API (SODA) binary. This is logged once for each media stream when the SODA binary is loaded. evliu@google.com chrome-media-ux@google.com Records when a user toggles the "hide profanity" option in settings. evliu@google.com chrome-media-ux@google.com Records when a user pins or unpins the Live Caption bubble. evliu@google.com chrome-media-ux@google.com Logged when the Live Caption bubble appears and disappears. Stream start indicates when the bubble appears due to an audio session starting. Stream end indicates when the bubble disappears due to a tab change, a navigation, or the audio session ending and the bubble fading out due to inactivity. Close button clicked indicates when the bubble disappears due to a user clicking the close button on the caption bubble. evliu@google.com chrome-media-ux@google.com Whether the verification of the Speech On-Device API (SODA) component failed due to a mismatch of the component architecture. Logged once during the verification step of the SODA component installation on Windows only. evliu@google.com chrome-media-ux@google.com The language code used to initialize the speech recognition service. Logged once when getting the Speech On-Device API (SODA) config path to use with the speech recognition service. evliu@google.com chrome-media-ux@google.com Whether the speech recognition session contains any recognized speech. This is logged once per media stream upon the destruction of the SpeechRecognitionRecognizerImpl. evliu@google.com chrome-media-ux@google.com Whether the Live Caption feature is enabled. This is logged once when the Live Caption controller is initialized on platforms that support Live Caption. caott@google.com cros-edu-eng@google.com Records the target language of a translation of live captions from the student in School Tools app. Records once per translation requested for live captions from the student in School Tools app. evliu@google.com chrome-media-ux@google.com Records the number of characters sent to the translate service. Records once per session upon the destruction of the LiveCaptionSpeechRecognitionHost. evliu@google.com chrome-media-ux@google.com Records when a user enables or disables the Live Translate feature from {Entrypoint}. Warning: this histogram was expired from 2024-06-13 to 2024-08-15; data may be missing. danft@google.com evliu@google.com Records the total latency of a successful translation request to the LiveTranslate.GetTranslation. This includes time spent in all dispatchers (e.g., on-device and fallback to Google API). danft@google.com evliu@google.com chrome-media-ux@google.com Records the source language of a request to the LiveTranslate.GetTranslation. danft@google.com evliu@google.com chrome-media-ux@google.com Records the target language of a request to the LiveTranslate.GetTranslation. danft@google.com chrome-a11y-core@google.com Records the latency of a successful translation coming from the GoogleApi. danft@google.com chrome-a11y-core@google.com Records the result coming from the GoogleApi (true or false). danft@google.com chrome-a11y-core@google.com Records the specific error reason when an on-device live translation request fails. danft@google.com chrome-a11y-core@google.com Records the latency of a successful translation coming from on-device-translation. danft@google.com chrome-a11y-core@google.com Records the result coming from on-device-translation (true or false). evliu@google.com chrome-media-ux@google.com Records the source language of a request to the Cloud Translate service. Recorded once per call to the Cloud Translate service. evliu@google.com chrome-media-ux@google.com Records the target language of a request to the Cloud Translate service. Recorded once per call to the Cloud Translate service. evanliu@google.com chrome-accessibility-eng@google.com Records the result of a URL load for the TranslationDispatcher. This is used to track the success and failure rates of translation requests. evanliu@google.com chrome-accessibility-eng@google.com Records the result of parsing the JSON response for the TranslationDispatcher. This is used to track the success and failure rates of parsing translation responses. abigailbklein@google.com chrome-a11y-core@google.com The result of the Screen2x run to identify a main node in the accessibility tree. The result could successfully identify a main node; could identify an invalid node; or could return a result after a previous had already labeled a main node. lucasradaelli@google.com kenjibaheux@google.com chrome-a11y-core@google.com Whether Chrome has enabled accessibility support because the user passed the --force-renderer-accessibility flag on the command-line (logged once after startup). lucasradaelli@google.com chrome-a11y-core@google.com Whether individual accessibility mode flags are set. Tracked when each mode flag is flipped from false to true. These flags are flipped automatically when software communicates with Chrome via accessibility APIs. Flags can only be flipped off by advanced users or for debugging using chrome://accessibility/ - and that isn't tracked in this histogram. jessejames@chromium.org rsorokin@chromium.org alemate@chromium.org cros-oac@google.com Delay between login_prompt_visible and Chrome OS OOBE startup sound playback. Depends on sound subsystem initialization time. katie@chromium.org chrome-a11y-core@google.com Whether the Chrome OS OOBE startup sound is enabled (logged once per profile load (signin screen or user profile)). kristislee@google.com chrome-a11y-core@google.com komo-eng@google.com Records the time taken to build the accessibility page tree using heuristic algorithms. Logged once per PDF page. dtseng@chromium.org kyungjunlee@google.com chrome-a11y-core@google.com When a PDF is constructed for accessibility, true if the PDF is tagged as specified by ISO 14289-1 (PDF/UA). kyungjunlee@google.com chrome-a11y-core@google.com Record when PDF is opened with {A11yFeature} with or without PDF OCR. kyungjunlee@google.com chrome-a11y-core@google.com Records the number of OCRed pages in the PDF file opened by Select-to-Speak users on ChromeOS. kyungjunlee@google.com chrome-a11y-core@google.com Records the number of pages in an inaccessible PDF when a PDF accessibility tree gets created for the PDF. This metric is only recorded when accessibility features are enabled. kyungjunlee@google.com chrome-a11y-core@google.com Records the time difference between when a ChromeVox user starts reading OCRed content in MediaApp and when the user reads it most recently. nektar@chromium.org chrome-a11y-core@google.com Tracks how many PDFs were opened in the Media App while the ChromeVox screen reader is enabled, which causes the PDF to be OCRed. kyungjunlee@google.com chrome-a11y-core@google.com Records the reading progression of a11y users in OCRed content in MediaApp in percentage. The reading progression (RP) is calculated with the following formula: RP = greatest visited page number / page count * 100. dtseng@chromium.org chrome-a11y-core@google.com Tracks time spent in AccessibilityTreeSnapshotCombiner::~AccessibilityTreeSnapshotCombiner. The primary use is to measure the impact of https://crrev.com/c/5410696, which updates the class to eliminate potential copies. kevers@chromium.org chrome-a11y-core@google.com Tracks the size of dirty tree serialization from the renderer to the browser process. Logged every time the document layout is clean and we need to update the accessibility tree. Low priority updates may be batched and sent every 150ms if a change was detected. Warning: This histogram was expired from 2025-04-13 to 2026-04-22, data may be missing. kevers@chromium.org chrome-a11y-core@google.com Tracks the contribution of {DataType} valued properties to the overall size of dirty tree serialization from the renderer to the browser process. Logged every time the document layout is clean and we need to update the accessibility tree. Low priority updates may be batched and sent every 150ms if a change was detected. kevers@chromium.org chrome-a11y-core@google.com Tracks the size of entire tree (snapshot) serialization from the renderer to the browser process. Snapshots are on demand when the entire a11y tree needs to be send from the renderer to the browser process. mschillaci@google.com olivierli@chromium.org chrome-a11y-core@google.com Tracks time spent in AXTree::Destroy. The primary use is to measure the impact of https://crrev.com/c/3937946, which updates AXTree to internally use a std::map instead of a base::flat_map. Please see the CL description for more context and a performance profile. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. dtseng@chromium.org chrome-a11y-core@google.com Tracks time spent in AXTreeCombiner::Combine. The primary use is to measure the impact of https://crrev.com/c/5410696, which updates the class to eliminate potential copies. Warning: this histogram was expired from 2025-05-04 to 2026-04-22, data might be missing. dtseng@chromium.org chrome-a11y-core@google.com Tracks time spent on the browser main thread handling requests for children on Mac. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. dtseng@chromium.org chrome-a11y-core@google.com Records if children need to be re-built on a request for children in the Mac accessibility tree. mschillaci@google.com lucasradaelli@google.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the browser main thread handling accessibility events sent from the renderer process and processed by BrowserAccessibilityManager. Accessibility.Performance.HandleAXEvents can still often record values when processing is relatively cheap because we exit before handing off the nodes to BrowserAccessibilityManager for various reasons (e.g. BFCache). This histogram only measures events which are processed by BrowserAccessibilityManager and thus should have a better histogram to understand the cost of doing so, and be used to meaure optimizations. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. mschillaci@google.com lucasradaelli@google.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the browser main thread handling location changes sent from the renderer process and processed by BrowserAccessibilityManager. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. lucasradaelli@google.com mschillaci@google.com lucasradaelli@google.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the render process executing the lifecycle stage FinalizingTree. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. mschillaci@google.com lucasradaelli@google.com chrome-a11y-core@google.com Tracks time spent on the browser main thread handling accessibility events sent from the renderer process. Logged each time the method is run without returning early. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. dtseng@chromium.org chrome-a11y-core@google.com Tracks time spent in ui::MergeAXTreeUpdates. The primary use is to measure the impact of https://crrev.com/c/5413915, which updates the function to eliminate potential copies. lucasradaelli@google.com mschillaci@google.com lucasradaelli@google.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the render process executing the accessibility stage ProcessDeferredUpdates. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. mschillaci@google.com lucasradaelli@google.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the render process sending pending accessibility events. Logging commences after loading is complete and triggered each time the method is run without returning early. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. mschillaci@google.com lucasradaelli@google.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the render process sending pending accessibility events. Logged each time the method is run without returning early. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. lucasradaelli@google.com mschillaci@google.com lucasradaelli@google.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the render process executing the lifecycle stage Serialize. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. mschillaci@google.com lucasradaelli@google.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the render process sending pending accessibility location changes. Logged each time the method is run without returning early. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. lucasradaelli@google.com mschillaci@google.com lucasradaelli@google.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the render process executing all the accessibility lifecycle stages that run when layout is clean. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. lucasradaelli@google.com janewman@microsoft.com janewman@microsoft.com kevers@chromium.org chrome-a11y-core@google.com Tracks time spent on the browser process unserializing accessibility updates. Logged each time the method is run without returning early. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. lucasradaelli@google.com kschmi@microsoft.com janewman@microsoft.com dlibby@microsoft.com chrome-a11y-core@google.com Tracks time taken to execute the public Windows API that {API}. This is recorded for all Windows users that call into our public APIs. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. Warning: this histogram was expired from 2025-05-04 to 2026-04-22, data might be missing. lucasradaelli@google.com javiercon@microsoft.com janewman@microsoft.com benjamin.beaudry@microsoft.com chrome-a11y-core@google.com The time to execute a call to the UMA_API_ELEMENT_PROVIDER_FROM_POINT method on a View by an accessibility tool. Recorded once for every call. Warning: This metric may include reports from clients with low-resolution clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports will cause this metric to have an abnormal distribution. When considering revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the solution. kristislee@google.com komo-eng@google.com Records the time from when the user intiates speech via the play button in Read aloud to when audio starts, or fails to start due to user action. The latter could indicate latency is too long. abigailbklein@google.com chrome-a11y-core@google.com Records the user-chosen color theme for the Read Anything panel. alfredohiguera@google.com chrome-a11y-core@google.com Records the skip or evaluation status when assessing the distillation quality of a page inside Reading Mode. This covers both browser-side skips (empty snapshots, HTML size bounds, etc.) and utility-side extraction failures, as well as final evaluation successes. Recorded once for every evaluation attempt. alfredohiguera@google.com chrome-irm-devs@google.com Records the {Metric} metric for Reading Mode distillation quality. Recorded as a percentage after multiplying the original 0.0-1.0 value by 100. Recorded after a successful distillation quality evaluation on a page. davidsegovia@google.com ammedina@google.com chrome-a11y-core@google.com Records the URL scheme present when Reading Mode distillation is triggered while the IsReadAnythingWithReadabilityEnabled flag is active. kristislee@google.com komo-eng@google.com Records whether distillation was successful after opening Reading mode via the omnibox chip. Note: prior to late July 2026 (approximately M152), this incorrectly was recorded when distillation was still running. lwinston@google.com chrome-irm-devs@google.com Records whether the page has at least 2 headers each of its top two headers, excluding h1 if there is exactly 1 h1. Recorded when the content is successfully distilled and updated in the Reading Mode panel. lwinston@google.com komo-eng@google.com Records {CountMetric}. Recorded when the content is successfully distilled and updated in the Reading Mode panel. lwinston@google.com komo-eng@google.com Records {RatioMetric}. Recorded when the content is successfully distilled and updated in the Reading Mode panel. abigailbklein@google.com chrome-a11y-core@google.com Records when the Read Anything panel displays the empty state and whether a user does a selection after it's shown. kristislee@google.com komo-eng@google.com Records which entrypoint is used to open Reading mode after showing the omnibox chip. abigailbklein@google.com chrome-a11y-core@google.com Records the user-chosen font name for the Read Anything panel. abigailbklein@google.com chrome-a11y-core@google.com Records the user-chosen font scale for the Read Anything panel. gusmartin@google.com chrome-irm-devs@google.com Records whether Reading Mode was closed before the UI was fully shown to the user. Recorded when the Reading Mode entry is hidden, except during transitions between presentation modes. abigailbklein@google.com chrome-a11y-core@google.com Records the language of the web page shown in Read Anything after the corresponding AXTree is distilled. abigailbklein@google.com chrome-a11y-core@google.com Records the user-chosen letter spacing for the Read Anything panel. kristislee@google.com komo-eng@google.com Records the user-chosen line focus mode for Read Anything when the panel is closed. kristislee@google.com komo-eng@google.com Records when the keyboard shortcut to toggle line focus is used, and whether it was used to enable or disable line focus. kristislee@google.com komo-eng@google.com Records the length of time the user spends in Reading mode with line focus on. This is measured from when line focus is enabled to when the user disables line focus or hides Reading mode. kristislee@google.com komo-eng@google.com Records the total distance moved with line focus in a session, either via mouse movement or via scroll. kristislee@google.com komo-eng@google.com Records the total number of lines highlighted or underlined with line focus in a session, either via keyboard arrow keys or with Read aloud speech. abigailbklein@google.com chrome-a11y-core@google.com Records the user-chosen line spacing for the Read Anything panel. martinglopez@google.com chrome-irm-devs@google.com Records whether audio playback successfully started within 5 seconds after the user selected the "Listen to this page" context menu item and sustained continuous playback for at least 2 seconds. gusmartin@google.com chrome-irm-devs@google.com Records whether a text selection was present in the main browser tab at the moment Reading Mode was opened. Recorded once per Reading Mode session (Open to Close), excluding tab switches or view-mode transitions. abigailbklein@google.com chrome-a11y-core@google.com Records the time taken to distill a web page using the merged algorithm that combines results from the rules based algorithm and the ML model. Refer to AXTreeDistiller::Distill for details. kristislee@google.com komo-eng@google.com Records when the Read Anything panel distills a new page and whether the user uses Read Aloud to play the text aloud for the new page. kristislee@google.com komo-eng@google.com Records the decision to show or hide the Reading mode omnibox chip and why. abigailbklein@google.com chrome-a11y-core@google.com Records when the Read Anything omnibox icon is shown. kristislee@google.com komo-eng@google.com Records whether the Read Anything panel is opened within a certain amount of time after the omnibox IPH is shown. Approximates whether or not the IPH influenced the user to open the panel. kristislee@google.com chrome-a11y-core@google.com Measures the duration a user spent reading a {PageType} page in {ViewMode} view mode. Logged when the page is changed, or the panel is closed or destroyed. lwinston@google.com chrome-a11y-core@google.com Logged when a page is opened in Reading Mode and the page language is English. Estimates whether a section with a heading containing key points related keywords ("Key points", "Summary", "TL;DR", "Takeaways", "What to Know") was present in the distilled reading mode content. This is a heuristic guess and not 100% accurate. lwinston@google.com chrome-a11y-core@google.com Logged when a page is opened in Reading Mode and the page language is English. Estimates whether a section with a heading containing key points related keywords ("Key points", "Summary", "TL;DR", "Takeaways", "What to Know") was present on the original webpage. This is a heuristic guess and not 100% accurate. kristislee@google.com komo-eng@google.com Records the total count of {HeadingLevel} headings distilled from a PDF document. This is logged once per distilled PDF document to analyze document structure complexity and distribution of heading levels (as opposed to logging each heading type as a separate categorical enum sample). kristislee@google.com komo-eng@google.com Records the ratio of headings to paragraphs on the distilled PDF. This is logged once per distilled PDF document. kristislee@google.com komo-eng@google.com Records the number of paragraphs distilled from a PDF. This is logged once per distilled PDF document gusmartin@google.com chrome-irm-devs@google.com Records selection attempts that occur before the Readability distillation has successfully mapped its content to the original page's AXTree. This is recorded at most once per navigation, for either a selection from the Side Panel or the Main Panel. This metric helps measure if the text alignment algorithm is fast enough for user interactions. martinglopez@google.com chrome-irm-devs@google.com Records the number of links in the Readability distillation with the given {Status}. This is recorded when the content is successfully updated in the Reading Mode panel. gusmartin@google.com chrome-irm-devs@google.com The percentage of characters in the distilled Readability output that were successfully mapped back to an AXNode in the original page. Recorded once per successful mapping attempt. gusmartin@google.com chrome-irm-devs@google.com Records the time taken for the {Step} phase of the Readability text alignment algorithm. Recorded once per successful mapping attempt. lwinston@google.com komo-eng@google.com Records the installed TTS engine version of the format yyyymmdd0 for the date + revision number of the installed engine ajitnarayanan@google.com kristislee@google.com ammedina@google.com komo-eng@google.com Records the user-chosen highlight granularity for reading aloud in the Read Anything panel. There was an error in the enum before 2025-07-22. This shouldn't affect the release of the feature to stable but use caution when interpreting results before that date. kristislee@google.com komo-eng@google.com Records which language the user is using to read aloud text in the Read Anything panel. ericchao@google.com ammedina@google.com chrome-a11y-core@google.com Enum value that tracks whether a Read Aloud speech session was started in the side panel or in the immersive overlay mode. Recorded when playback begins. lwinston@google.com komo-eng@google.com Records when the user changes a read aloud speech setting in the Read Anything panel. kristislee@google.com komo-eng@google.com Records which kind of voice the user is using to read aloud text in the Read Anything panel. This is recorded when speech stops, either from user action or when speech completes, to avoid blocking speech. lwinston@google.com komo-eng@google.com Records how often the user changes the voice for reading aloud in reading mode from one langauge to another. This excludes automatic voice language changes done directly from reading mode. kristislee@google.com komo-eng@google.com Records the user-chosen voice speed for reading aloud in the Read Anything panel. lwinston@google.com komo-eng@google.com Records the count per session of the number of Read Aloud {Action} actions. kristislee@google.com komo-eng@google.com Records whether action requests received by the ReadAnythingUntrustedPageHandler (e.g. link click or image download requests) are from the currently observed tree. If not, this may be a malicious request. abigailbklein@google.com chrome-a11y-core@google.com Records the time taken to distill a web page using the rules based algorithm. Refer to AXTreeDistiller::DistillViaAlgorithm for details. abigailbklein@google.com chrome-a11y-core@google.com Records when a scroll happens. alfredohiguera@google.com chrome-a11y-core@google.com Records when the user triggers an action from the settings menu in the Read Anything panel. abigailbklein@google.com chrome-a11y-core@google.com Records when the user changes a text style setting in the Read Anything panel. gusmartin@google.com chrome-irm-devs@google.com Records how long Reading Mode overlay was active, regardless of whether it was shown in the side panel or in the immersive view. Recorded when the feature is hidden or closed (capped at 24 hours). Difference with SidePanel.ReadAnything.ShownDuration is that this metric records sessions for immersive view also (Only records if read-anything-immersive-reading-mode is enabled). If read-anything-immersive-reading-mode is disabled use SidePanel.ReadAnything.ShownDurationMax1Day instead. gusmartin@google.com chrome-irm-devs@google.com Recorded when Reading Mode is opened. Tracks the trigger that caused it to open. martinglopez@google.com chrome-irm-devs@google.com Records when Immersive Reading Mode opens in side panel mode because the distillation was empty. This metric captures the original trigger for opening Reading Mode (e.g. Omnibox, Context Menu) or the Toggle trigger. lwinston@google.com chrome-a11y-core@google.com Records when a speech error event is captured with Read Anything Read Aloud. lwinston@google.com komo-eng@google.com Records the length of time of a speech playback session from play to pause or from play to speech stopped, either due to reaching the end of content or an error. To not disrupt any active experiments, this metric will remain, but in a few milestones the team will evaluate if the metric below can replace this entirely. kristislee@google.com komo-eng@google.com Records the length of time of a speech playback session from play to pause or from play to speech stopped, either due to reaching the end of content or an error. Recorded for a {PageType} in {ViewMode}. kristislee@google.com komo-eng@google.com Records when speech stops and why. lwinston@google.com komo-eng@google.com Records the installation state of the WASM TTS extension engine whenever a system voice is used. This is intended to help understand when system voices are being used over natural voices. martinglopez@google.com chrome-irm-devs@google.com Records the time elapsed from when the browser triggers OnActiveAXTreeIDChanged (due to page navigation, or sidebar opening) to when the AXTree is ready in the Read Anything App model. martinglopez@google.com chrome-irm-devs@google.com Records the time elapsed from when the browser triggers OnActiveAXTreeIDChanged (due to page navigation, or sidebar opening) to when the WebUI finishes layout and renders the distilled text content in the viewport. lwinston@google.com komo-eng@google.com Records the time from when opening the Read Anything side panel entry first triggers the renderer and when the WebUI connects. martinglopez@google.com chrome-irm-devs@google.com Records the time it takes for the Readability distiller to complete a distillation process. This starts when StartDistillation is called and ends when OnArticleReady is called. gusmartin@google.com chrome-irm-devs@google.com Measures the latency of successful distillations via the readability engine triggered by active accessibility tree ID changes. The interval starts when Reading Mode detects that the active accessibility tree ID has changed and ends when the readability engine successfully finishes extracting the distilled article content. This metric is only recorded for successful distillations resulting from initial active tree changes. It explicitly excludes background updates, failed distillations, or sub-document navigations (such as Single Page Application updates) to ensure a clean baseline for evaluating distillation pipeline performance. lwinston@google.com komo-eng@google.com Records the time from when opening {Flow} first is triggered and when its {Method} is called. lwinston@google.com kristislee@google.com martinglopez@google.com komo-eng@google.com chrome-irm-devs@google.com Records the word count of the distilled content {Type}. Uses built-in web segmenter to count words using the page language. (See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Segmenter) kristislee@google.com komo-eng@google.com Records an estimate of how many words were heard via Read aloud before switching pages or closing Reading mode. This is very accurate if the voice being used to speak supports word boundaries (e.g. Google's Natural voices), but may not be very accurate when the voice does not support word boundaries, especially for languages that don't separate words with whitespace. ammedina@google.com kristislee@google.com komo-eng@google.com Records an estimate of how many words were seen in the Reading mode panel before switching pages or closing Reading mode. Currently works only for languages that separate words with whitespace. lucasradaelli@google.com janewman@microsoft.com chrome-a11y-core@google.com Tracks the type of failure that occured when unserializing the accessibility tree. When an error in unserialization occurs, this is emitted and unserialization aborts. In the case of a tree with multiple issues, only the first error is recorded. Refer to AXTree::Unserialize for details. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. rhalavati@chromium.org chrome-a11y-core@google.com Records if the component was available or could be downloaded when it was needed. If not available, it also records if the network connection existed or not. rhalavati@chromium.org chrome-a11y-core@google.com Records the number of times that the component installation has failed as DLC service was busy and retried before successful install. rhalavati@chromium.org chrome-a11y-core@google.com Records if ScreenAI library is compatible with the device. The metric is recorded when component updater or DLC downloader check if the library should be downloaded. rhalavati@chromium.org chrome-a11y-core@google.com Records the result of Screen AI DLC installation. rhalavati@chromium.org chrome-a11y-core@google.com Records a Screen AI library load result on Windows. The result is recorded after initialization of Screen AI service and loading chrome_screen_ai.dll. rhalavati@chromium.org chrome-a11y-core@google.com Records the time taken to run main content extraction when it has {result} to return non empty results. rhalavati@chromium.org chrome-a11y-core@google.com Records if a request to Main Content Extraction feature of ScreenAI service returned non empty results. This metric is recorded only for requests that are sent to the Screen2x library and did not fail in preprocessing steps. rhalavati@chromium.org chrome-a11y-core@google.com Records the client type of each OCR request. rhalavati@chromium.org chrome-a11y-core@google.com Records the client type of the OCR requests that have width or height above the threshold that results in downsampling. rhalavati@chromium.org chrome-a11y-core@google.com Records the client type of each failed OCR request. rhalavati@chromium.org chrome-a11y-core@google.com Records the number of pixels in the passed image to OCR from PDF, when the output had {Result}. rhalavati@chromium.org chrome-a11y-core@google.com Records the latency for an OCR request in Screen AI service for an image with width and height {DownsampleStatus} downsampling threshold. rhalavati@chromium.org chrome-a11y-core@google.com Records the number of lines that OCR recognized for an image. rhalavati@chromium.org chrome-a11y-core@google.com Records the number of lines that OCR recognized for an image sent from PDF. rhalavati@chromium.org chrome-a11y-core@google.com Records the number of times that OCR mode was switched between light and normal during lifetime of the service. It's recorded only when service is shutting down due to being idle. rhalavati@chromium.org chrome-a11y-core@google.com Records the language that is detected most when OCR is performed on a PDF page. rhalavati@chromium.org chrome-a11y-core@google.com Records if a request to Optical Character Recognition feature of ScreenAI service was successful or not. rhalavati@chromium.org chrome-a11y-core@google.com Records how long an OCR request in Screen AI service takes for a PDF request. abigailbklein@google.com rhalavati@chromium.org kyungjunlee@google.com chrome-a11y-core@google.com Records the time taken to distill a web page for cases where the action {Result}. It's being emitted each time whenever it distills or fails to distill a page. for Screen2x. Refer to ScreenAIService::ExtractMainContentInternal for details. rhalavati@chromium.org thestig@chromium.org chrome-a11y-core@google.com Tracks if screen reader mode was enabled in the browser when PDF Searchifier added text to a PDF. This metric is recorded only once for each PDF, and records the status when searchify adds the first text to the page. If screen reader status changes after the first page is searchified, it's not recorded. The metric is recorded when browser is in screen reader compatible mode and it does not necessarily mean that a screen reader is running on the OS. rhalavati@chromium.org chrome-a11y-core@google.com Records when ScreenAI service does not get a reply from the library in one minute after a request. Records if the request was for OCR or not. rhalavati@chromium.org chrome-a11y-core@google.com Records true if the system environment is vulnerable to glibc DTV TLS allocation races (glibc < 2.35 with Static TLS pool exhausted) when Screen AI OCR initialization is attempted, or false otherwise. This metric is recorded during Screen AI OCR initialization, only on Linux and when glibc is used. rhalavati@chromium.org chrome-a11y-core@google.com Records how long it takes to initialize {ServiceName} functionality in Screen AI service. rhalavati@chromium.org chrome-a11y-core@google.com Records if initialization of {Step} in Screen AI service was successful or not. dtseng@chromium.org chrome-a11y-core@google.com Whether the result of a scroll to make visible accessibility action is performed on an image node. This roughly corresponds to accessibility focus on an image. Logged from ChromeVox (ChromeOS) and BrowserAccessibilityManager (non-ChromeOS). lucasradaelli@google.com aluh@chromium.org chrome-a11y-core@google.com Accessibility node roles where kSetValue is being called on. This should help us determine whether we can deprecate kSetValue. Recorded whenever a set value action is requested on an accessibility node. evliu@google.com chrome-media-ux@google.com Whether a VTT file contains an embedded style block. Recorded when a VTT file is parsed. evliu@google.com chrome-media-ux@google.com Records whether the render frame can use on-device speech recognition. Recorded each the time a speech recognition session is started and on-device speech recognition is requested. evliu@google.com chrome-media-ux@google.com Recorded when Web Speech API relaxes the user activation requirement for downloading a language pack because it is present in the Accept-Language header. evliu@google.com chrome-media-ux@google.com Logged errors fired by the Web Speech API. Logged each time the ErrorOccurred event of the Web Speech API is fired. evliu@google.com chrome-media-ux@google.com Records whether the Gemini Nano model is available for Web Speech API. Recorded each time a speech recognition session is started and Gemini Nano is requested. evliu@google.com chrome-media-ux@google.com Records whether on-device speech recognition is installed for the requested language. Recorded each the time a speech recognition session is started and on-device speech recognition is requested. evliu@google.com chrome-media-ux@google.com Records whether on-device speech recognition is supported on the device. Recorded each time the SodaInstaller is initialized during post profile init. evliu@google.com chrome-media-ux@google.com Records whether the TinyGemma model is available for Web Speech API. Recorded each time a speech recognition session is started and TinyGemma is requested. evliu@google.com chrome-media-ux@google.com Whether on-device speech recognition available for use with the Web Speech API. Logged when the speech recognition session is created. evliu@google.com chrome-media-ux@google.com Recorded when a Web Speech API speech recognition session starts. Logs true if the requested language is present in the user's Accept-Language header (navigator.languages). This serves as a proxy metric to estimate the usage of language packs downloaded via the relaxed user activation flow, though it may overcount packs installed through other legitimate means. evliu@google.com chrome-media-ux@google.com Logged when the processLocally attribute is explicitly set on the SpeechRecognition interface. evliu@google.com chrome-media-ux@google.com Whether the audio forwarder is used for the Web Speech API. Logged when the speech recognition session is created. evliu@google.com chrome-media-ux@google.com Whether on-device speech recognition is used for the Web Speech API. Logged when the speech recognition session is created. evliu@google.com chrome-media-ux@google.com Measures the duration of a call to the WebSpeech API. Recorded once per call to the Open Speech API that powers the WebSpeech API. evliu@google.com chrome-media-ux@google.com Logged errors fired by the Web Speech API. Logged each time the ErrorOccurred event of the Web Speech API is fired. lucasradaelli@google.com benjamin.beaudry@microsoft.com chrome-a11y-core@google.com janewman@microsoft.com Records which Windows accessibility client APIs (UIA, MSAA/IA2, or both) have been actively used during the lifetime of the process. Recorded once per UMA upload interval when the kNativeAPIs accessibility mode is active. Unlike Accessibility.Win.RequestedClientApis, this only tracks API calls that led to functions which may potentially modify the process-wide AXMode. lucasradaelli@google.com benjamin.beaudry@microsoft.com chrome-a11y-core@google.com janewman@microsoft.com Records which Windows accessibility client APIs (UIA, MSAA/IA2, or both) were requested via WM_GETOBJECT during the lifetime of the process. This is an upper-bound signal recorded once per UMA upload interval regardless of whether the kNativeAPIs accessibility mode is active. lucasradaelli@google.com nektar@chromium.org chrome-a11y-core@google.com Tracks usage of all public Windows accessibility APIs. lucasradaelli@google.com nektar@chromium.org dlibby@microsoft.com chrome-a11y-core@google.com Tracks properties requested via UI Automation GetPropertyValue(). Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. lucasradaelli@google.com almaher@microsoft.com benjamin.beaudry@microsoft.com janewman@microsoft.com javiercon@microsoft.com chrome-a11y-core@google.com Tracks presence of UI Automation core library (in process). lucasradaelli@google.com almaher@microsoft.com Tracks which Windows high contrast theme is set in system settings (logged once after startup). AccessibilityHighContrastColorScheme::None indicates that high contrast mode is not enabled. lucasradaelli@google.com benjamin.beaudry@microsoft.com chrome-a11y-core@google.com Tracks if the JAWS version predates the fix for Chrome’s UIA support. True if the version is newer or exactly JAWS 2022.2402.1, 2023.2402.1, 2024.2312.99, or 2025. False otherwise. lucasradaelli@google.com benjamin.beaudry@microsoft.com chrome-a11y-core@google.com Tracks the major version of JAWS detected. Recorded when the AXMode in the browser process changes, usually when an AT connects or at launch when an AT is already connected. lucasradaelli@google.com benjamin.beaudry@microsoft.com chrome-a11y-core@google.com Tracks the major version of NVDA detected. Recorded when the AXMode in the browser process changes, usually when an AT connects or at launch when an AT is already connected. kenjibaheux@google.com lucasradaelli@google.com chrome-a11y-core@google.com Whether Windows system settings show that Sticky Keys are enabled. lucasradaelli@google.com benjamin.beaudry@microsoft.com chrome-a11y-core@google.com Records the base::PersistentHash of the lowercased process name of a UIA client when it disconnects from Chrome's UI Automation provider. Helps measure how often Chrome receives disconnect signals. This exploratory metric may be replaced by richer disconnect telemetry. Only available on Windows build 26100 (24H2) or later. lucasradaelli@google.com benjamin.beaudry@microsoft.com chrome-a11y-core@google.com Records the base::PersistentHash of each distinct lowercased UIA client process basename connected when the existing AXMode metrics record {AXModeFlag}. Use the corresponding Accessibility.ModeFlag count as the denominator. Multiple different clients can be recorded for the same AXMode snapshot, but duplicate process basenames are recorded once. Only available on Windows build 26100 (24H2) or later. lucasradaelli@google.com chrome-a11y-core@google.com Tracks whether the third-party ZoomText screen magnifier is running on Windows. lucasradaelli@google.com mschillaci@google.com chrome-a11y-core@google.com - Tracks whether a screen reader is enabled -- {ScreenReader}. rhalavati@chromium.org chrome-a11y-core@google.com Records the number of {ServiceName} service crashes before one successful shutdown. It is recorded when the service shuts down due to being idle, and had crashed before and restarted. rhalavati@chromium.org chrome-a11y-core@google.com Records if launching the {ServiceName} service was successful or not. rhalavati@chromium.org chrome-a11y-core@google.com Records how long it took for the {ServiceName} service to {Result}. rhalavati@chromium.org chrome-a11y-core@google.com Records if {ServiceName} service was suspended due to crash. Recorded when a client asks for service availablity or for connection to the service. rhalavati@chromium.org chrome-a11y-core@google.com Records the duration of {ServiceName} service. The metric is stored after the process shuts down or crashes. rhalavati@chromium.org chrome-a11y-core@google.com Records the maximum memory usage of {ServiceName} service. The metric is stored after the process shuts down or crashes and up to 1GB and only if the process runs for more than one second. wylieb@google.com chrome-reader-mode-team@google.com Records the score for the ada boost model for negative scores (scores that prevent pages from showing). This model is used to determine if any given page is suitable for distillation. Recorded for every page load. Note: Incorrect before M140. wylieb@google.com chrome-reader-mode-team@google.com Records the score for the ada boost model for positive scores. This model is used to determine if any given page is suitable for distillation. Recorded for every page load. Note: Incorrect before M140. wylieb@google.com chrome-reader-mode-team@google.com For all distillation page signals, records if the distillation result made it within the magic toolbar button timeout. Recorded when ReaderModeActionProvider gets a distillation result. wylieb@google.com chrome-reader-mode-team@google.com For distillable pages, records if the distillation result made it within the magic toolbar button timeout. Recorded when ReaderModeActionProvider gets a distillation result. wylieb@google.com evanluo@google.com chrome-reader-mode-team@google.com The entry-point into Reader Mode for a certain {TabType}, recorded when the user enters reader mode. wylieb@google.com evanluo@google.com chrome-reader-mode-team@google.com Records the font family set by the user in the distilled page prefs UI. wylieb@google.com evanluo@google.com chrome-reader-mode-team@google.com Records the font scaling set by the user in the distilled page prefs UI. Value can range from 100% to 250% in 25% increments. wylieb@google.com evanluo@google.com chrome-reader-mode-team@google.com Records the links enabled setting set by the user in the distilled page prefs UI. wylieb@google.com chrome-reader-mode-team@google.com Records whether the reader mode accessibility setting is enabled. Recorded when ReaderModeManager gets a distillation result. wylieb@google.com chrome-reader-mode-team@google.com Records the end-state of the distillation result. This is different from the triggering model result because it also includes android business logic. Recorded when ReaderModeManager gets a distillation result. wylieb@google.com chrome-reader-mode-team@google.com Records various events that happen in the Reader Mode Contextual Page Action. These represent a funnel of user actions starting from eligibility to click-through. wylieb@google.com chrome-reader-mode-team@google.com Records the user's "show links" preference. Logged when the user clicks the "show links" button in the reading mode preferences bottom sheet. wylieb@google.com chrome-reader-mode-team@google.com Records the user's "show links" preference. Logged when the user clicks the "show links" preference in a11y settings. wylieb@google.com evanluo@google.com chrome-reader-mode-team@google.com Records the theme set by the user in the distilled page prefs UI. gusmartin@google.com chrome-reader-mode-team@google.com Records whether distilling the page resulted in sucess, parse failure, or no Data to distill wylieb@google.com chrome-reader-mode-team@google.com Records the end result when determining if given page is distillable. Recorded for every page load. wylieb@google.com chrome-reader-mode-team@google.com Records the score for the ada boost model for negative scores (scores that prevent pages from showing). This model is used to determine if any given page is suitable for distillation. Recorded for every page load. Note: Incorrect before M140. wylieb@google.com chrome-reader-mode-team@google.com Records the score for the ada boost model for positive scores. This model is used to determine if any given page is suitable for distillation. Recorded for every page load. Note: Incorrect before M140. mdjones@chromium.org wylieb@google.com chrome-reader-mode-team@google.com Records if the panel became visible at any point after a page was navigated. wylieb@google.com chrome-reader-mode-team@google.com The amount of time the distiller script spent running on the page. This is includes loading the script onto the web page. Recorded after the user has chosen to view a simplified version of the current page. wylieb@google.com chrome-reader-mode-team@google.com Records the amount of time it takes for the reader mode signal to make it to SignalAccumulator. Recorded when the distillation result is passed to CPA. Only recorded on Android. mdjones@chromium.org wylieb@google.com chrome-reader-mode-team@google.com Records the amount of time a user spent on a Reader Mode Page. Recorded when the user exits reader mode. Only recorded on Android. wylieb@google.com chrome-reader-mode-team@google.com Records the word count for the distilled page. Recorded when the page distillation result is received. Recorded per-page even if the article has multiple pages (e.g. a continue reading button). katie@chromium.org chrome-a11y-core@google.com Pumpkin installation is triggered when one of the features using Pumpkin (currently the only feature using Pumpkin is Dictation) are enabled. This histogram is recorded once when Pumpkin installation finishes with either success or failure. Warning: this histogram was expired 2023-11-30 to 2024-02-29 and 2025-05-04 to 2026-04-22, data might be missing. abigailbklein@google.com evliu@google.com yilkal@chromium.org Soda Installation is triggered when one of the features using SODA (e.g. Live Caption, Projector, Offline Dictation) are enabled. Records whether SODA binary installation succeeded. This is recorded once when SODA installation attempt finishes with either success or failure. abigailbklein@google.com evliu@google.com yilkal@chromium.org Soda Installation is triggered when one of the features using SODA (e.g. Live Caption, Projector, Offline Dictation) are enabled. Records the time taken for the binary installation to complete with {Result}, recorded at the end of the attempt. abigailbklein@google.com evliu@google.com yilkal@chromium.org Soda Installation is triggered when one of the features using SODA (e.g. Live Caption, Projector, Offline Dictation) are enabled. Records whether SODA language pack installation succeeded or not. This is recorded once when SODA language pack installation attempt finishes with either success or failure. abigailbklein@google.com evliu@google.com yilkal@chromium.org Soda Installation is triggered when one of the features using SODA (e.g. Live Caption, Projector, Offline Dictation) are enabled. Records the time taken for the SODA language pack installation for {SodaLanguageCode} to complete with {Result}, recorded at the end of the attempt. evliu@google.com chrome-a11y-core@google.com Recorded when a SODA language pack is redownloaded (registered) after having been previously uninstalled due to the 30-day expiration timer. This is recorded as true when the language pack is requested to be installed again. evliu@google.com chrome-a11y-core@google.com Recorded when a SODA language pack is uninstalled due to the 30-day expiration timer, which occurs if the language pack has not been used by any feature relying on SODA for 30 days. This is recorded as true when the uninstallation occurs. evliu@google.com chrome-a11y-core@google.com Recorded when the browser starts and initiates a preemptive download of the SODA binary and default language pack. This happens exactly once per user installation if the kPreemptiveSodaDownload feature is enabled. It is recorded as true when the preemptive download is triggered. dtseng@chromium.org katie@chromium.org chrome-a11y-core@google.com Events fired by the text-to-speech engine when speaking an utterance. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. dtseng@chromium.org katie@chromium.org chrome-a11y-core@google.com Counts when playback starts and stops on the audio element via the canplaythrough and ended events. katie@chromium.org chrome-a11y-core@google.com When the user requests a download of a text-to-speech voice, records the success/failure result, and service used to download it. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. dtseng@chromium.org katie@chromium.org chrome-a11y-core@google.com Indicates if an utterance spoken via synthesized text-to-speech was triggered by the Chrome TTS extension API or the web speech API. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. katie@chromium.org chrome-a11y-core@google.com True if an utterance spoken via synthesized text-to-speech requested a specific voice by name. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. katie@chromium.org chrome-a11y-core@google.com True if an utterance is spoken with native speech provided by the operating system, otherwise it's spoken via a Chrome extension that implements text-to-speech support. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. dtseng@chromium.org chrome-a11y-core@google.com The rate of an utterance to be spoken via synthesized text-to-speech. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. joelriley@google.com katie@chromium.org chrome-a11y-core@google.com ChromeOS source that triggered text-to-speech utterance via extension API, from a few known accessibility clients (Select-to-speak, ChromeVox). Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing. katie@chromium.org chrome-a11y-core@google.com The length of an utterance to be spoken via synthesized text-to-speech. Warning: this histogram was expired 2023-11-30 to 2024-02-29, data might be missing.