Examine source code of Start Page Layout Builder

{
  "manifest_version": 3,
  "name": "__MSG_extensionName__",
  "version": "1.0",
  "description": "__MSG_extensionDescription__",
  "permissions": [
    "storage"
  ],
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "action": {
    "default_icon": {
      "128": "icons/icon-128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b3e2a5c1-0d8e-8d0e-5f0c-1b5f33dfd5cd}",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "collects_data": false
      }
    }
  }
}