Examine source code of AlwaysGonnaGiveYouUp

{
  "manifest_version": 2,
  "name": "AlwaysGonnaGiveYouUp",
  "version": "1.1",
  "description": "Block's Never gonna give you up",
  "icons": {
    "49": "icons/icon-49.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/watch?v=dQw4w9WgXcQ"
      ],
      "js": [
        "alwaysgonnagiveyouup.js"
      ]
    }
  ],
  "applications": {
    "gecko": {
      "id": "{dd359116-1d0e-4af1-abcc-d3d488261a0e}"
    }
  }
}