The weberdns.de zone hosts many weird DNS records which are helpful in testing and configurations and see how they handle these entries.

Some examples of hosted entries:

ttl-0s.weberdns.de with a TTL of 0 seconds
loop.weberdns.de a CNAME loop of length 2
64a.weberdns.de with 64 A records
many-rrs.weberdns.de with a wide mix of record types for ANY queries
abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz1234567890.weberdns.de for long domains and labels
áàăâåäãąąāæćĉčċçďđéèĕêěëėęēğĝġģ.weberdns.de to test umlauts
Domains for SRV, HINFO, CAA, LOC, TLSA, SSHFP, and OPENPGPKEY records