Examine source code of Better Tabz

{
  "manifest_version": 3,
  "name": "Better Tabz",
  "version": "1.0.4",
  "description": "Overrides the default new tab page.",
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "permissions": [
    "bookmarks"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "bettertabz@gccody.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "128": "favicon.png"
  }
}