Examine source code of URL-Shortner-By-Narayan

{
  "manifest_version": 2,
  "name": "URL-Shortner",
  "version": "1.0",
  "description": "Shorten URLs using Bitly API",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4532e840-c551-4359-9232-c5af2d081a72}"
    }
  }
}