Examine source code of killfullscreenmode

{
  "manifest_version": 2,
  "name": "killfullscreenmode",
  "version": "1.1resigned1",
  "description": "Exits fullscreen mode for the first window once per second. A horrible hack I wrote to work around a bug in which my Firefox browser will automatically enter fullscreen mode randomly.",
  "background": {
    "scripts": [
      "killfullscreenmode.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{00862cc0-d3ee-4772-ab0b-f4c202dcad8f}"
    }
  }
}