WPT details: https://github.com/web-platform-tests/wpt/tree/master/credential-management
The Federated Credential Management API allows users to bring their federated identity to login to websites in a manner compatible with improvements to browser privacy.
https://github.com/fedidcg/FedCM
Docs: https://github.com/fedidcg/FedCM
Explainers: https://github.com/fedidcg/FedCM