The Tree View tab shows you file specifics such as file Name, Path location (where on your computer it came from), Status of the transmission and size information.  If a file(s) failed the backup job, the tree view is a great place to revisit the details of that file and see WHY it failed.

While you are in the List View, press the PLUS next to the Drive letter, then folder, then any subfolders, to expand the Tree.  Click on the file name to view the details of that single file.