This NIP is not yet in main. Here is an overview of PRs referencing this NIP.
NIP-57: Clarify multiple relays in zap request event MERGED @vicariousdrama
update nip-57 zap receipt spec to include 'a' tag MERGED @huumn
NIP-57: drop `description_hash` validation for zaps OPEN @callebtc
Fix typos about inline code MERGED @erechorse
Fix NIP-57 typo MERGED @jmateoac
NIP-57 - Zap Proofs / Partially complete zap receipts OPEN @Egge7
Clarify NIP-57 Appendix G purpose OPEN @mikedilger
Adds Zap splits to NIP-57 MERGED @vitorpamplona
Uncle Bob's Observations from the field OPEN @unclebob
Minor Fixes of NIP-57 MERGED @jiftechnify
Implement Markdownlint GitHub action OPEN @mariano-perez-rodriguez
Markdown improvements, embelishments, and standardizations CLOSED @mariano-perez-rodriguez
added pubkey zap-tag OPEN @Egge7
Event-specific zap markers MERGED @pablof7z
Update all NIPs to include 'depends' and 'mentions' tags OPEN @blakejakopovic
Re-write nip 57 to consolidate flow and clarify terminology MERGED @staab
Polls RFC 69 OPEN @toadlyBroodle
NIP-57: add optional a tag for tipping nip-33 coordinates MERGED @verbiricha
nip57: add lnurl tag to prevent custodial replay attacks OPEN @jb55
NIP-57: Add amount tag to zap request MERGED @Semisol
make zaps independent from lnurl and other minor tweaks CLOSED @fiatjaf
NIP-57: Lightning Zaps MERGED @jb55