Is your suggestion related to a problem? Please describe.

Sometimes I will join a room that has limited history visibility and think, "Wait, why don't I see anything in the timeline? Is this a bug?"

Describe the solution you'd like.

There should be something like the preamble that you see at the beginning of rooms, except for the beginning of visible history. In addition to showing the room's name, avatar, and topic, it should briefly explain why history before this point is unavailable (for example maybe it's not because of history visibility rules, but because of encryption).

Describe alternatives you've considered.

Alternatively the limited history visibility message could go in a tile and be kept separate from any room preamble. Either way, a preamble at the start of visible history would be helpful for reassuring users that the timeline has in fact loaded when they join new rooms.