canonical

Canonical determines whether this is the main parent for the space. When a user joins a room with a canonical parent, clients may switch to view the room in the context of that space, peeking into it in order to find other rooms and group them together. In practice, well behaved rooms should only have one canonical parent, but given this is not enforced: if multiple are present the client should select the one with the lowest room ID, as determined via a lexicographic utf-8 ordering.