[Cthulhu_]

Where do you (or curl) draw the line of what is a different OS though? Because I can imagine that on a low enough level they may be the same, work the same, etc. Same kernel, CPU architectures, etc. That is, how much code in (in this case) curl is specific to iOS and WatchOS?

[pjmlp]

I am not spending time researching this, however since Network.framework was introduced in 2018, that sockets are considered the old way, and modern applicaitons should use NWConnection instead.

See WWDC 2018 session,

"Introducing Network.framework, A modern alternative to sockets"