Examine source code of Tabby Cat

{
  "manifest_version": 2,
  "name": "Tabby Cat",
  "version": "0.996resigned1",
  "description": "A new friend in every new tab.",
  "author": "Leslie Zacharkow",
  "offline_enabled": true,
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "chrome_url_overrides": {
    "newtab": "public/index.html"
  },
  "developer": {
    "name": "Leslie Zacharkow",
    "url": "http://www.lesliez.com"
  },
  "homepage_url": "http://tabbycats.club",
  "browser_specific_settings": {
    "gecko": {
      "id": "{f7f203e0-9d1d-4557-891f-9865877c5b48}"
    }
  }
}