Examine source code of Classic Twitter UI

{
  "name": "Classic Twitter UI",
  "manifest_version": 2,
  "version": "1.0.2resigned1",
  "description": "Simply revert the new Twitter.com appearance.",
  "author": "dangeredwolf",
  "permissions": [
    "https://www.twitter.com/",
    "https://twitter.com/",
    "http://www.twitter.com/",
    "http://twitter.com/",
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://twitter.com/*",
        "https://www.twitter.com/*",
        "http://twitter.com/*",
        "http://www.twitter.com/*"
      ],
      "js": [
        "extension/classictwitter.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{bfc268f3-b65c-4fb3-ad24-fe5385bdde62}"
    }
  }
}