@dahukanna @hazelweakly It literally is JSON over HTTP and the identifier is the URL, intrinsically tied to a hostname. So the meaning of moving posts to a new server is not obvious, and that's why Mastodon hasn't attempted it.
CalcKey copies history apparently. I don't know what decisions they have made around it.
If I migrate from hostsrc to hostdst and my post hostsrc/B refers to post hostsrc/A, should hostdst/B get rewritten to refer to hostdst/A?
If hostsrc is also a CalcKey, does it set up redirects so that any edits to hostdst/C can be seen by people who go to hostsrc/C? If hostdst sends out edits to hostdst/C, will any receiving servers know to apply the edits to their local copy of hostsrc/C?