wtf lol, you can put a . at the end of a domain and it works:

https://chee.party./tag/music/

I've just learnt by clicking what I thought was a poorly-formed historical link on info.cern.ch, lol

EDIT

jake tracked this down in the spec:

The rightmost domain label of a fully qualified domain name in DNS may be followed by a single "." and should be if it is necessary to distinguish between the complete domain name and some local domain.rfc3986

surprised i haven't come across this