I must have gotten very lucky, because I downloaded and installed installed Classic Shell on a fresh Windows 10 install yesterday afternoon and was not affected

I must have gotten very lucky, because I downloaded and installed installed Classic Shell on a fresh Windows 10 install yesterday afternoon and was not affected - the installer bore the right signature and my system is intact and boots fine. If I had tried a few hours later, I would probably be reinstalling Windows 10 for the second time in 2 days.