Examine source code of X Be Gone

{
  "manifest_version": 2,
  "name": "X Be Gone",
  "version": "1.0",
  "description": "Removes the ugly X from Twitter and replaces it with the original Twitter logo.",
  "icons": {
    "16": "icons/xbegone-16.png",
    "48": "icons/xbegone-48.png",
    "128": "icons/xbegone-128.png",
    "512": "icons/xbegone-512.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.twitter.com/*"
      ],
      "js": [
        "xbegone.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "files/twitter.ico"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e45d0d1c-7e53-48fc-8250-89190927dbe0}"
    }
  }
}