Examine source code of Fullscreen Everywhere

{
  "manifest_version": 2,
  "name": "fullscreen everywhere",
  "version": "1.1resigned1",
  "icons": {
    "16": "logo-16.png",
    "32": "logo-32.png",
    "64": "logo-64.png"
  },
  "description": "Allows you to use fullscreen mode in all videos in any website (works only for youtube and dailymotion videos, and natives ones)",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "script.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f2734f89-a12c-4188-af7d-7d956b4c4e4c}"
    }
  }
}