Windows Longhorn - a cancelled Windows version that was one of the earliest examples of Frutiger Aero
Wasn't this the codename for an early version of Vista?
Yeah it was internal name for Vista.
XP was Whistler, and 7 was Vienna
Here are others: https://en.m.wikipedia.org/wiki/List_of_Microsoft_codenames#Windows_NT_family
Longhorn is like a concept car. Yeah it looked great but by the time the sausage was made it wouldn’t be close to what we imagined. The PT Cruiser of operating systems. Kind of like Apple’s Copland.
Foghorn?
Leghorn