Examine source code of Google App Launcher

{
  "manifest_version": 2,
  "name": "Google App Launcher",
  "version": "1.3",
  "description": "Adds a button to the toolbar with easy access to your favorite Google applications",
  "homepage_url": "https://github.com/asolkar/ffx-addon-gglappbtn",
  "icons": {
    "48": "icons/icon.png"
  },
  "applications": {
    "gecko": {
      "id": "@gglappbtn",
      "strict_min_version": "80.0"
    }
  },
  "permissions": [
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/gglappbtn-icon-32.png",
    "default_title": "Google Applications",
    "default_popup": "data/gapps.html",
    "theme_icons": [
      {
        "light": "icons/gglappbtn-dark-icon-32.png",
        "dark": "icons/gglappbtn-icon-32.png",
        "size": 32
      }
    ]
  },
  "options_ui": {
    "page": "data/options.html"
  }
}