Hide All Regions ⌥↑
Collapses the Project Audio listing to hide all of the regions. You are left with the list of audio files only.
NB this keyboard combination has multiple uses. It will transpose audio/events up if you use it in a tracks window.
The Project Audio Browser lists all audio files in your project, along with information about file sampling rate, bit depth, format (mono/stereo), and size. Within the Project Audio Browser, you can sort, group, and rename your audio files.