Many of you should be old enough to remember that there have already been two versions of Windows that began with the number 9, specifically Windows 95 and Windows 98.

To save time, some third-party Windows desktop developers used a shorthand to check the version name (not number) of Windows they were installing their app to. Instead of coding apps to check for Windows 95 or Windows 98, developers coded instructions to check for "Windows 9."

That made sense since there were only two versions of Windows that had a nine in their name to that point. It was simply an easier way to figure out which version of Windows the program was dealing with.