I'm pretty sure all the NS* calls and references in MacOS are from NextSTEP.

Yes, but it's not like this is some hidden legacy stuff, that you're not supposed to encounter. This is part of the public macOS API: https://developer.apple.com/documentation/appkit/nstext

Every AppKit and Foundation type uses the NS prefix, and will keep doing so for any foreseeable future. New NS types are added to these frameworks each macOS release.

Mission control is not supposed to print the name of the control/window visible to the user though, surely, which is what the article is talking about.

It is.

Citation: I was a NeXTSTEP developer.

Seems like most people think the NS prefix stands for NeXTSTEP. What do you think?

Maybe you should've googled this before you commented

I’m not a Mac developer: what does the NS stand for?

NeXTSTEP.

Objective-C doesn't have namespaces (like C), so people use two-letter prefixes on their types to prevent name clashes. The NS prefix is used by Apple's Foundation and AppKit frameworks, that originated from NeXTSTEP, hence NS.

It is; in MacOS NSText is a Cocoa API which arrived and evolved from NeXTstep.

Tell me you're ignorant about computer science history, without telling me you're ignorant about computer science history.

codepoet80

there, just told you

it absolutely is.