Examine source code of YouTube Smart Pause

{
  "manifest_version": 2,
  "name": "YouTube Pause on Tab Switch",
  "version": "1.1",
  "description": "Pauses YouTube videos when switching tabs, with toggle functionality",
  "applications": {
    "gecko": {
      "id": "{d78e7aee-ff5d-4391-a4a5-ee802c827c8c}"
    }
  },
  "permissions": [
    "storage",
    "*://*.youtube.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "page_action": {
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    },
    "default_title": "YouTube Pause Toggle"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ]
}