[cm/pub/] with Classic McEliece 6960-119+X25519.

Combined Classic McEliece 6960-119 and X25519 public keys are used
for KEM purposes, so should have "kem" key usage set.

Its algorithm identifier is "mceliece6960119-x25519". Its
public key value is a concatenation of 1047319-byte
mceliece6960119 public key and 32-byte X25519 one.

Public key's fingerprint should be calculated using SHAKE128.

=> X2559 key-agreement algorithm
=> RFC 7748, same
=> Classic McEliece KEM algorithm
=> SHAKE XOF function

Optional "/load/v/prehash" field can contain the SHAKE256 hash
of the concatenated public keys in "/load/v/pub/0", that could
save resources during [cm/kem/mceliece6960119-x25519-hkdf-shake256]
KDF calculations.