How much code is needed to implement Classical+PQ (Hybrid PQ) or PQ-only (Only PQ) cipher selection restrictions just?
FWIU, with golang:
# This allows X25519MLKEM768 (Hybrid PQ)
GODEBUG=fips140=on
# This prevents any PQ ciphers from being used:
GODEBUG=fips140=only
tlsref needs to be revised to specify PQ cipher lists.