Completed: https://gist.github.com/fiatjaf/ea7d21e81359e1eb8abcb8805306adaa?permalink_comment_id=4484926#gistcomment-4484926
tl;dr 5M sat bounty to make https://github.com/fiatjaf/no-fed work.
ActivityPub communication is between servers. A server talks to another server, pushing and pulling data. Identities live on servers. Nostr communication is between clients and servers.