Having run into a few more examples of this with different ActivityPub software, I think there are a couple of distinct things to considerthe plumbing of communicating between two connecting networks or sites: via a shared protocol ("federation", if it's ActivityPub), via a connector that speaks both protocols (a bridge or hub), via a client, or by a low-tech method like cut-and-paste or export/importmapping the semantics and presentation of content across somewhat-0compatble software. With ActivityPub, the standard and agreed-on FEPs provide some basis for this; so do Lexiscons for AT Protocol -- but they don't actually fully solve the problem. When you're mapping across protocols, you don't even have that.So techniques for cross-protocol mapping are more general, and can also apply to the single-protocol case (and potentially be specialized to take advantage of protocol-specific information). But protocol-specific work doesn't generalize to cross-protocol situations. @laurenshof @snarfed.org @mackuba @quillmatiq