Use Room Title
The window title of group chats is currently the part before @ in MUC JID, and the heading in the banner is the JID. The pre-@ part is also used for bookmarks.
This is often not very descriptive? And since XMPP-MUC has a "Room Title" field, why not use it?
\<iq to="firstname.lastname@example.org" type="get"> \<query xmlns="http://jabber.org/protocol/disco#info" /> \</iq>
iq/query/identity/@name as heading, window title, default bookmark name etc.