Examine source code of Extension Update Checker

{
  "manifest_version": 2,
  "name": "Extension Update Checker",
  "version": "1.4.3",
  "author": "kgersen",
  "description": "If a user has disabled automatic add-on updates, this extension may be used to notify the user if there are available updates.",
  "permissions": [
    "storage",
    "management",
    "notifications",
    "menus"
  ],
  "optional_permissions": [
    "<all_urls>",
    "https://versioncheck.addons.mozilla.org/*"
  ],
  "background": {
    "page": "background.html",
    "persistent": true
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": false
  },
  "icons": {
    "48": "icons/blue/blue-48-1.png",
    "96": "icons/blue/blue-96-1.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/blue/blue-16-1.png",
      "32": "icons/blue/blue-32-1.png"
    },
    "default_area": "navbar"
  },
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "110.0",
      "id": "{ad9c9bad-5977-4160-87a4-19f30b30bcb9}"
    }
  }
}