I think NT is correct; NT was designed by Dave Cutler, who famously worked on VMS stuff before working for Microsoft. I think the poster was correct in posting NT.
But NT 3.1 is a completely different OS to Windows 3.1.
They might look the same, but one has OS/2 heritage while the other has DOS heritage (to overly simplify their origins, but I’m in a rush this morning so can share more accurate details later if you wish).
Edit: the GP changed their comment. The original copy didn’t reference NT, it just said “Windows 3.1”. Hence my reply.
the worst example of "second system effect" i have ever heard of
not windows 3.1 -- windows 3.1 was popular! Windows before 3.1 was distinctly unpopular. It had basically no installed base. The only Windows 2.x applications I know of actually shipped an embedded Windows copy on the floppy disk.
HP was carefully tracking all the much less popular stuff Microsoft was doing in the late 80s because they thought this "WIMP" paradigm had staying powers, even if Microsoft was not exactly selling a lot of units