I think the current interface should be improved.

• we don't make any difference between the window string identifier (for persistent window geometry) and window title. Both are called "name" everywhere and it is quite confusing and error prone: e.g. what about translations? Any given window will have one set of entries in the preferences for each language I use TeXmacs in.
• SLOT_NAME should be called SLOT_WINDOW_TITLE or we should add this new slot.

I think we should:

• have plain_window_widget() set the window's orig_name (internal identifier, unique) and
• after creating the widget, we set the title with send(SLOT_WINDOW_TITLE, "translated window title or whatever")