Whenever a chatroom is created, it gets some name (and also a description, if the room creator fills it in). Later the room topic can be changed by room owners or moderators, every such event is shown in the room transcript. (As you can check by searching for messages such as "room topic changed to ...".)
Still, the original room name is not shown in any place in the transcript. (Only the subsequent changes are shown.) I am not aware of any way to find out the name which the room got when it was created.
Suggestion: When a room is created, include the original room topic in the transcript.