This is very cool. I did some digging. the v6 address "2a0d:eb00:8006::1" belongs to a hackerspace (https://bgp.wtf). so they probably worked with the hackerspace to get 6.0.0.8.0.0.b.e.d.0.a.2.ip6.arpa to delegate to their dns servers, which is run by them (https://sdomi.pl/weblog/22-servfail-the-first-100-days/). and with that they pointed 1.<ipv6-block>.ip6.arpa to cloudflare's nameserver and served A records from there. I think??
https://1.6.0.0.8.0.0.b.e.d.0.a.2.ip6.arpa/@domi/statuses/01JJS6BMXVDJTQFTRVX4ZKR2GW