This only supports two addresses as the intended use is 1 IPv4 and 1 IPv6
address on a single-homed host, and the only supported configuration of
outgoing connections to other servers is to bind a single IPv4 or IPv6
address.
These operate on the SubjectPublicKeyInfo of the certificate, which does
change unless the private key is changed. This allows the fingerprint to
stay constant even if the certificate is reissued.
(The same fingerprint is also used by DANE)