One of the craziest aspects of IPv6 implementation is the reverse DNS lookups.
IPv6 uses ip6.arpa and segments each little nybble into a subdomain!
https://en.wikipedia.org/wiki/Reverse_DNS_lookup#IPv6_revers...
This means there are always 32 octets to a reverse-IPv6 address, and there are no shortcuts or macros to overcome this! That means if you wish to assign a singular name that maps from a legitimate /64 Network ID, you must populate 64 bits worth of octets in a zone with this data. It is an absurd non-solution. This never should've been allowed to happen, but it will basically mean that ISPs abandon reverse DNS entirely when they migrate to IPv6 implementations.