Examine source code of YoutubeLiker

{
  "manifest_version": 2,
  "name": "srcAddon",
  "version": "1.0",
  "description": "likes every Youtube Video",
  "icons": {
    "48": "instalike.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/watch?v=*"
      ],
      "js": [
        "instalike.js"
      ]
    }
  ]
}