I did try to look at them using WinZip (from a Win10 sys) and, while I could open a file, it showed as empty. Is there another Win10 based program that allows me to view the files? Or should I be using something on the Debian/OSMC system to do that (like, would nano work)?
No - the files in the cache folder are just the downloads. They always have their data...They just need to be uncompressed first.