Fediverse

Email is already nicely federated, but I think it's time for a change. Services like protonmail offer encryption between users, but you can't host your own instance. It would be awesome if there was a spec somewhere for a federated email service that defines

• email encryption between users
• markdown
• ~~connection with activity pub? (What would this look like)~~ I mean some way to email the activity pub, ie: add comments via email
• compatibility with standard email users (if you send/receive to/from a user who does not have email v2 implemented it just uses normal features)
• maybe "smart attachments" for money transfers, calender invites, etc.
• somehow better support for email discussion groups
• this spec should be focused heavily on usage for humans instead of automated mailing, I expect html would not be defined.

I'm just spit balling here. Does anyone have any ideas? Does something like this exist?

Thanks, Evan