Examine source code of YouTube Continue Watching

{
  "manifest_version": 3,
  "name": "YTWatch",
  "version": "2.0",
  "icons": {
    "600": "icons/ytwatch.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/feed/history"
      ],
      "js": [
        "bg.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d6644483-8707-4d33-a420-322cba22b6a1}"
    }
  }
}