Examine source code of Fingerinator

{
  "manifest_version": 2,
  "name": "Fingerinator",
  "version": "1.0",
  "description": "The fan favorite Chrome extension that replaces 'Mike' with 'Finger' is now on Firefox!",
  "icons": {
    "48": "icons/finger-48.png",
    "96": "icons/finger-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "finger.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{921b8c4b-a9a1-4c36-b251-3e36dc6ee6ce}"
    }
  }
}