We have C, Python and Java libraries released right now, all of which are beta WIP as we don't yet have any users who can inform the API designs from real world use cases.
I'm thinking of writing a Django-webauthn library (although I'm not sure if it would just be simpler to fork django-u2f). Would the Python library help at all? It looks like it's for USB communication and not for general helpers around signing/authentication/etc.
It's mostly for host-authenticator communications, yes, but it it includes a couple of helpers for verifying signatures. But you're right it's not a full-featured server library at this point.
https://github.com/Yubico/libfido2
https://github.com/Yubico/python-fido2/
https://github.com/Yubico/java-webauthn-server