Errata patches for ssh-keygen have been released for OpenBSD 6.7. When attempting to download resident keys from a FIDO token that does not require a password/PIN, ssh-keygen would crash with a NULL dereference.
Binary updates for the amd64, i386, and arm64 platforms are available via the syspatch utility. Source code patches can be found on the errata page: https://www.openbsd.org/errata67.html