Examine source code of Tab Grouping by Domain

{
  "manifest_version": 2,
  "name": "Tab Grouping by Domain",
  "version": "1.0",
  "description": "Automatically group tabs by their domain for better organization",
  "permissions": [
    "tabs",
    "activeTab",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Tab Grouping by Domain",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "{93883955-d749-48ad-95af-5d421570d074}"
    }
  }
}