Examine source code of Gooey Startpage

{
  "manifest_version": 2,
  "name": "Gooey Startpage",
  "description": "Replace default new tab page in Firefox with Gooey Startpage.",
  "version": "1.2.1",
  "developer": {
    "name": "Jacob Druery",
    "url": "https://github.com/PullRequestTimeout"
  },
  "icons": {
    "48": "icons/gooey-48.png",
    "96": "icons/gooey-96.png"
  },
  "permissions": [
    "geolocation",
    "storage"
  ],
  "chrome_settings_overrides": {
    "homepage": "index.html"
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{fee82983-1d7d-4038-b73c-17fbf0ffb047}"
    }
  }
}