In https://ripe80.ripe.net/archives/chat/88/

13:23 < luna> https://ipv4flagday.net/
13:24 < chrbre_AS206228> https://github.com/ipviolations/ipv4flagday/issues

Thanks, Luna and Christian, for pointing me at this, which is a fine idea.
I’ve added an issue for false alarm when zone apex has no address record of either kind.

Niall