Examine source code of Youtube Ends At

{
  "manifest_version": 2,
  "version": "1.9.1",
  "default_locale": "en",
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png",
    "128": "icons/icon-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/*"
      ],
      "js": [
        "scripts/content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "youtube-ends-at@gonguet.com"
    }
  }
}