Examine source code of AutoTube

{
  "description": "Adds a switch to toggle auto replay of the current YouTube video",
  "manifest_version": 2,
  "name": "AutoTube",
  "version": "1.0",
  "homepage_url": "https://github.com/Sarayalth/AutoTube",
  "icons": {
    "1280": "icons/icon1280.png"
  },
  "content_scripts": [
    {
      "matches": [
        "http://www.youtube.com/*",
        "https://www.youtube.com/*"
      ],
      "js": [
        "ytauto.js"
      ]
    }
  ]
}