However, so much work had been pushed into the Blackcomb release that it was clear that it couldn’t all be done in one release cycle, so selected portions were extracted into an interim release code named Longhorn, which is the name of a bar situated between the Whistler and Blackcomb mountains.
Longhorn was the code name for Windows Vista.

https://devblogs.microsoft....0190722-00/?p=102724
Теперь понятно, почему Виста получилась такой кривой.