Request: allow room display name /myroomnick and room avatars override global display name and avatar

[Mikaela]

I was told that this is the most appropiate repository for this.

I generally wish to be known by my global displayname, but there are a few rooms where I would like to have a different name and then there are a few dozen rooms where I would like to be known by my full name as they are somewhat professional. Currently when I change my display name in Element by /nick, the rooms that I have a separate name in get overwritten and then I have to start going through them by /myroomnick again.

This also affects room specific avatars.

[Sorunome]

AFAIK synapse changing m.room.member event in all rooms you are in when changing profile is actually behaviour not mentioned in the spec - the spec doesn't say what servers should do if you change your profile information

So, while there is a need to clarify that, it is also a good idea to make local room changes "sticky".

[uhoreg]

Duplicate of https://github.com/matrix-org/matrix-doc/issues/545

[tulir]

This is a duplicate of matrix-org/matrix-spec#323, not matrix-org/matrix-spec#103