This toolbar is displayed at the top of each file display (assuming the option to use a toolbar for the File Display border is turned on in Preferences).
The elements on this toolbar are:
If you right-click (or click and hold with the left button) the button a
drop-down menu is displayed that contains a number of links to special
locations, for quick navigation. It also contains a menu of your recent locations. For
users upgrading from Opus 9, this drop-down is the equivalent of the old "Go"
menu (and you can still press Alt+G to open it).
The remaining elements are not actually part of the toolbar - they are part of the underlying File Display border.