Examine source code of YouTube Video Looper

{
  "manifest_version": 2,
  "name": "YouTube Video Looper",
  "version": "1.0.0",
  "description": "Toggle looping for YouTube videos",
  "permissions": [
    "*://*.youtube.com/*",
    "activeTab"
  ],
  "browser_action": {
    "default_icon": {
      "48": "icons/loop-48.png",
      "96": "icons/loop-96.png"
    },
    "default_title": "YouTube Looper"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{64d46600-8f74-4df2-8b1b-77d5b2b670a8}"
    }
  }
}