Examine source code of AutoLoop

{
  "manifest_version": 2,
  "name": "AutoLoop",
  "version": "1.4resigned1",
  "description": "Auto loops videos on youtube.",
  "icons": {
    "48": "icons/ytube.png"
  },
  "applications": {
    "gecko": {
      "id": "autoloop@tds.net",
      "strict_min_version": "45.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.youtube.com/watch?v=*"
      ],
      "js": [
        "AutoLoop.js"
      ]
    }
  ]
}