Your statement is just wrong. The project is not abandoned.
The FIDELIO Service id1.vx4.eu is available and up & running:
https://dev.ssllabs.com/ssltest/analyze.html?d=id1.vx4.eu

Who did you contact at my employer? There's no public support eMail from adesso for this service. My private inbox is full - I can't respond to everyone.

id1.vx4.eu has to call Governikus Autent eID-Service for the entitlement certificates.
There had been 3 issues in the past: 1) change of TR-03130 SOAP certificates of the eID-Service, 2) update of TLS certificate and linking to new eID access certificate, 3) currently: an unexpected 403 from the Governikus backend that can't be fixed by myself during Saturday night. The service had been running in between.

You seem to fully ignore that people may be on holidays, have a Covid infection or are on business trips. And this is a low-budget project, no big fancy or pay-per-use business model(!), that relies on me caring about such issues in my freetime.

Get yourself a hardware authenticator if you need it daily for GitHub.
(-> https://gitlab.com/adessoAG/FIDELIO/webauthn-eID4FF/-/issues/1)

2023-11-06: the service is up & running