My #ActivityPub developer guide moved to another repository: https://codeberg.org/silverpill/ap-next/src/branch/main/guide.md

It started as a FEP, but has evolved into something bigger.

About the repository:

As stated in the readme, ActivityPub Next is a project dedicated to evolving the ActivityPub protocol.

Currently it only contains the developer guide, but I think that more content will be added over time.