{
  "version": "1.0",
  "manifest_version": 3,
  "name": "Test extension for onMessage() handler promise that resolves return",
  "background": {
    "service_worker": "background.js"
  },
  "content_scripts": [{
    "matches": ["<all_urls>"],
    "js": ["content_script.js"],
    "run_at": "document_start"
  }]
}