This is closer to a shower thought, given I don’t really know much about how ActivityPub works. Has anyone, or is it even possible to, made an instance designed to work as say a FUSE file system?
I was mostly just thinking about how hard UIs are to make and thought “what if the content was the UI”.
Nextcloud can have some sort of federation: https://nextcloud.com/federation/
I find the idea kind of neat, but not very useful