What kind of files are these? They appear and disappear in Explorer

10C1C64FFDSC69827ABF

b7f63cc5ba627ee9391

Note the former is all caps while the later only lower case letters. Their locations in File Explorer seems to change a lot and they don't open. I made up these numbers because when I went to find them, I couldn't and don't know where they reside, I just run across them occasionally and have wondered for years what they are and now while doing some clean up, I get around to asking.

The numbers generally refer to a software install used instead of a name often searching for the code will tell you the software this gets rid of the rubbish and better than ccleaner and 100% free UnCleaner - Josh Cell Softwares