ResearchBitcoin Dev Archive BIPs
BIP 433: Pay to Anchor (P2A)
Applications, Informational, Draft. By Gregory Sanders. Never named in a subject line or discussed by number on the list.
In Bitcoin Core
First shipped in Bitcoin Core 28.0 .
Spending of Pay to Anchor (P2A) outputs is standard as of v28.0 (PR 30352).
From Bitcoin Core's doc/bips.md.
The threads, in order
No thread on the list names this BIP. Search the archive for its title if you think one should.