The window shows the last write date for the cursored file.
A LMB click in this window will sort the active file window with an ascending sort on file date and time. The simulated LED immediately below it will be green.
A RMB click in this window will sort the active file window with an descending sort on file date and time. The simulated LED immediately below it will be red.
If the active file window is sorted on another parameter, the simulated LED below it will be gray.