Examine source code of Watchtime Tracker

{
  "manifest_version": 2,
  "name": "Watchtime Tracker",
  "version": "1.6.1",
  "icons": {
    "16": "assets/icons/favicon-16.png",
    "32": "assets/icons/favicon-32.png",
    "48": "assets/icons/favicon-48.png",
    "64": "assets/icons/favicon-64.png",
    "128": "assets/icons/favicon-128.png"
  },
  "description": "Track your activity on Youtube and Twitch",
  "homepage_url": "https://analytics.lucask.dev/",
  "short_name": "Watchtime Tracker",
  "permissions": [
    "storage",
    "*://*.youtube.com/*",
    "*://*.twitch.tv/*",
    "tabs"
  ],
  "author": "xD33m",
  "applications": {
    "gecko": {
      "id": "xd33m@xd33m.github.com"
    }
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "assets/icons/favicon-16.png",
      "32": "assets/icons/favicon-32.png",
      "48": "assets/icons/favicon-48.png",
      "64": "assets/icons/favicon-64.png",
      "128": "assets/icons/favicon-128.png"
    },
    "default_title": "WatchtimeTracker",
    "browser_style": false
  },
  "background": {
    "scripts": [
      "js/background.bundle.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*",
        "*://*.twitch.tv/*"
      ],
      "js": [
        "js/contentScript.bundle.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "web_accessible_resources": [
    "js/hooker.bundle.js",
    "js/twitchHook.bundle.js"
  ]
}