Examine source code of Mobile Out

{
  "description": "This extension helps you to redirect mobile version of Facebook page to desktop version in just ONE CLICK.",
  "manifest_version": 2,
  "name": "Mobile Out",
  "version": "2.1.3resigned1",
  "homepage_url": "https://github.com/mpizza",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "96": "icons/icon96.png",
    "128": "icons/icon128.png",
    "1024": "icons/icon1024.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://m.facebook.com/*"
      ],
      "js": [
        "app.js"
      ],
      "css": [
        "button.css"
      ]
    }
  ],
  "web_accessible_resources": [
    "icons/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ae878113-4888-4d40-b842-04a523ee7eb4}"
    }
  }
}