FedBox filtering could be a start as notifications are loosely just the actor being present into the to field (normalization helps there), presence in the cc field being for the regular timeline.
Quite the same semantics as ~formal emails there.
Extension to ActivityPub, which Pleroma implemented. I wrote a standardization draft and ended up never posting it because of the bunch of changes and lack of examples in the Fediverse Enhancement Proposal project and the more discussion-oriented thread I started went nowhere.
I’ll likely end up posting it properly into litepub, here is the draft: https://hacktivis.me/tmp/uploadMedia.html
In my opinion the local client should never fetch remote posts by itself and instead always use the proxyUrl endpoint (which pleroma doesn’t have yet btw) so authentication can work with keeping the users’ key into the server as currently done.
Maybe FedBox filtering could work for this but I’d rather have something which embraces good full-text search rather than end up with something like grep(1).
You mean a Follow activity? Implementation defined again but I guess sending a second Accept/Reject would be an invalid activity, of course ActivityPub has basically no such thing as error messages…
There is the Read activity, only software I’m aware of which uses it is Honk.
Something like FedBox filtering could be used there I guess but there is a lack of a “Give me anything matching this, regardless of the endpoint/collection”