Examine source code of YouTube Auto Pause/Play

{
  "manifest_version": 2,
  "name": "YouTube Auto Pause/Play",
  "version": "1.1",
  "description": "Pauses YouTube video when the window loses focus and plays it when the window gains focus. Option to pause when switching tabs.",
  "permissions": [
    "tabs",
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a6f8ac83-c651-4174-acd7-0eba293cc4cd}"
    }
  }
}