Two FEPs are related to filtering:
- https://codeberg.org/fediverse/fep/src/branch/main/fep/5bf0/fep-5bf0.md
- https://codeberg.org/fediverse/fep/src/branch/main/fep/6606/fep-6606.md (cc @mariusor)
And there is one about synchronization: https://codeberg.org/fediverse/fep/src/branch/main/fep/8fcf/fep-8fcf.md
Nothing has been proposed for inclusion check yet, but I heard that Lemmy devs plan to implement it, see this discussion: https://socialhub.activitypub.rocks/t/fep-db0e-authentication-mechanism-for-non-public-groups/4197/5