As you browse a library, the toolbar offers two important controls for navigating your library. These come in handy as you start to explore folders and subfolders.
This button takes you up one folder in your Luminar library. As you navigate deeper into subfolders, you may want to see a parent folder. For example you may have a folder called Soccer, and inside a folder for each season of games. Inside of each season is a folder for each game. As you are working, the ability to move to a higher folder level may come in handy. This is particularly true when navigating in the Gallery View of the Library as it allows you to work with the Library panel hidden even.
Clicking the Current Location shows you a list of folders and the current file path you are exploring. This functionality is very similar to how a folder works in your computer operating system. Clicking on the button shows an ordered list, and you can choose a higher level folder to switch for browsing.