ResearchBitcoin Dev Archive BIPs
BIP 461: Deterministic ECDSA Signatures
Applications, Specification, Draft. By Liam Gilligan. Never named in a subject line or discussed by number on the list.
In Bitcoin Core
First shipped in Bitcoin Core 0.17.0 .
Deterministic ECDSA signatures with low-R grinding (at most 70 bytes when DER encoded) as of v0.17.0 (PR 13666).
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.