Examine source code of Fusk

{
  "manifest_version": 2,
  "name": "Fusk",
  "version": "1.1",
  "description": "Removes x.com monitised buttons",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.x.com/*"
      ],
      "js": [
        "retwit.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{fb561460-dd17-4f3f-80ac-dca7fe8ab91e}"
    }
  }
}