Current draft I'm working on here is: draft-davids-forsalereg-08.
https://datatracker.ietf.org/doc/html/draft-davids-forsalereg
https://forsalereg.sidnlabs.nl/rfc/
- https://forsalereg.sidnlabs.nl/ (associated registry group)
SIDN: https://www.sidn.nl/en/whois?q=example.nl
Demo-server from Tools: https://forsalereg.sidnlabs.nl/demo
( a good domain to test here is: testdns.nl)
TXT _for-sale.testdns.nl
(may not work at the demo above, because the demo uses an early, deprecated method)
The tools-directory contains a couple of scripts to validate the concept.