An optional manifest key enabling the use of an OAuth 2.0 security ID on the extension. This key takes an object with two required sub-properties: `"client_id"` and `"scopes"`. When developing an extension that uses an `"oauth2"` key, consider also setting the extension's [`"key"`](https://developer.chrome.com/docs/extensions/mv3/manifest/key) to keep a [consistent extension ID](https://developer.chrome.com/docs/extensions/mv3/tut_oauth#keep-consistent-id).

For more detailed implementation instructions, visit the full [OAuth 2.0 tutorial](https://developer.chrome.com/docs/extensions/mv3/tut_oauth).

````json
{
  // ...
     "oauth2": {
      "client_id": "YOUR_EXTENSION_OAUTH_CLIENT_ID.apps.googleusercontent.com",
      "scopes": ["https://www.googleapis.com/auth/contacts.readonly"]
    },
    "key": "EXTENSION_PUBLIC_KEY",
  // ...
}
```
````