Notices where this attachment appears
-
I found https://marc.info/?l=e-lang&m=97564104720495&w=4 . Apologies for marc.info's horrible styling.
I'm pretty sure I read about it on a proper web site, but this seems to be the same proposal.
Apparently it wasn't exactly what I said above, it was fingerprint only, and then some centralized service (ugh) would look up which fingerprint goes to which IP.
Later on in https://marc.info/?l=e-lang&m=98577007410712&w=4 an IP number is mentioned, but that's the IP number of a lookup server, not the http+tls server.