This NIP is not yet in main. Here is an overview of PRs referencing this NIP.
nip09: filtered deletation.  OPEN @kehiy
NIP-09: Adding relay implementation potential CLOSED @kehiy
format(all): JSON formatting MERGED @kehiy
style: fix header styles in same format MERGED @kehiy
Add functionality to exclude specified relays from deletion requests OPEN @0ceanSlim
Update NIP-09 to rename to deletion request MERGED @tyiu
Add k tag to deletions MERGED @staab
NIP-09: clarify "a" tag deletions MERGED @alexgleason
Deleting replaceable events OPEN @fiatjaf
NIP-09 Deletion Event Improvements OPEN @vitorpamplona
Clarify behaviour of kind:5 events for replaceable events OPEN @basantagoswami
Remove "NIP-33" mentions MERGED @AsaiToshiya
Remove all NIP authors MERGED @fiatjaf
NIP-09: Add `a` tag deletion MERGED @pablof7z
Minor JSON fix MERGED @AsaiToshiya
Add "z" as authorized deletion pubkey tag CLOSED @arthurfranca
Implement Markdownlint GitHub action OPEN @mariano-perez-rodriguez
Markdown improvements, embelishments, and standardizations CLOSED @mariano-perez-rodriguez
Update all NIPs to include 'depends' and 'mentions' tags OPEN @blakejakopovic
Minor typos and a correction to NIP-09 reference to pubkey MERGED @vasil9v
stronger wording for relay deletion behavior MERGED @khimaros