So if it's just about protocol to exchange files, SSH and webdav are the de-facto standards for that (FTP has declining popularity). If we're talking about the

So if it's just about protocol to exchange files, SSH and webdav are the de-facto standards for that (FTP has declining popularity). If we're talking about the semantics of building desktop applications, then i think you're looking for freedesktop.org, although it quite POSIX-centered. Higher-level, federated alternatives include ActivityPub (HTTP signatures + JSON ActivityStreams), XMPP (XML stanzas), Solid (HTTP + Linked Data). All four of these standards could receive extension proposals for more semantics for specific use-cases. However, Microsoft (who owns linked in) and other evil tech-multinationals will never adopt a standard because that would allow competitors to walk on their turf. Remember when gmail.com chat was federated with Jabber/XMPP until Google pulled the plug?