> There’s also no reason that the public facing name has to be the same as the internal name. They could have called it Windows 9 and internally reported it as anything in the apis.

This is what they were doing at the time anyway.

Windows 7 was 6.1, Windows 8 was 6.2, Windows 8.1 was 6.3.

The concern was about apps from the 90s.

Those were very poorly written apps. They very well could simply have been using APIs that returned the consumer oriented names.

These are custom apps running on a specific set of computers in places like banks, stores, government offices around the world, etc.

This is what Apple did when they finally dumped the OS X branding. macOS 15 also reports as 10.15.