Matrix: peeking over federation #45
Description
Currently you can only preview a room if at least one user of your homeserver has already joined the room.
This is quite annoying, especially for discovery using spaces (which are rooms under the hoods).
This would also unblock features that could be used as a base for a social network on Matrix, with Posca for example.
I wrote a PoC a while ago and got the complex part working, but the work is still unfinished.