I am on Windows 10.
Occasionally I will see a strange file that has a file name of 12 uppercase, random hexadecimal characters such as 1A2B3C4D5E6F with no file extension, be created in the root of my C: drive. The file contains a 40-character, random uppercase hexadecimal string, which I assume to be a hash. It seems like every time this shows up the file name and contents are different, and I've tried to Google both the file name and contents and have no results. The file is marked as 'hidden' and shows up across reinstalls, although seemingly randomly (it's not there when I first reinstall, but then a few weeks later if I just happen to check the root of my C: drive it will be there).
What are these files, what do they do, and why do they show up?