W3C Web Authentication specification
FIDO2 Client to Authentication Protocol
Web Authentication API - Web APIs | MDN
Java WebAuthn server
Python WebAuthn server and FIDO2 USB client libraries
C FIDO2 USB client libraries
Yubico: demo.yubico.com/webauthn
Microsoft: webauthntest.azurewebsites.net
Google: webauthndemo.appspot.com
FIDO-Dev Discussion List
W3C Web Authentication working group
OpenID Enhanced Authentication Profile (EAP) Working Group
Next: Terminology