This bar displays a path listing the views that where navigated through to reach
the currently open view.
It is not the same thing as the Views History accessed from the Main Toolbar, which shows all views opened or selected so far during a session.
The view history bar shows one possible path of Ancestor views the current view has, the one navigated through during the current session.
You can click on any view label in the path to re-open / go to that view.
If you first open a view from say the 'Find a Map/List' option on the Views Menu, or any of the other dialogs which allow you to open a view directly, you will get a text description of that starting point as the first element in the path, and this will not be navigable.
You can turn this bar on and off from the Views
Menu.