Examine source code of Bookmark Groups

{
  "manifest_version": 3,
  "name": "Bookmark Groups",
  "version": "2.0.0",
  "description": "Android-style folder grouping for bookmarks on New Tab",
  "browser_specific_settings": {
    "gecko": {
      "id": "bookmark-groups@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "bookmarks",
    "storage",
    "activeTab"
  ],
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  }
}