Hi bobbymcgee and Digerati. :smile9:
Sorry to say, but this statement isn't correct:
many disk cleanup programs, including CCleaner or Windows' own Disk Cleanup purge that location as a matter of routine
As seen through the link I provided above, Disk Cleanup does indeed clear out the Downloaded program folder.
Regardless, it does not change the fact the files saved in download folders are for temporary use and if needed, just download them again.
@bobbymcgee - it would probably be best if you told us specifically what files you are looking for.