The firefox version does not present FIDO2 PIN dialog for YubiKey 5C NFS
preventing passwordless login (e.g. google.com). Consequentially the passwordless
login does not work with currently packaged firefox.
The login works like a charm with Debian packaged chromium or firefox package
provided by mozilla.org (153.0esr (64-bit)).
I have installed additionally
https://github.com/mozilla/authenticator-rs
used as CTAP2 backend by mozilla.
The command
cargo run --example ctap2 --no-default-features --features crypto_openssl
works like a charm.
An additional detail: A dialog asking to touch the
key (instead of Key PIN dialog) pops up and disappear immediatelly.