Qt has grown so huge that I rather choose Tk or GTK for cross platform GUI.

i would love to see how Swift will do cross platform gui.

SwiftUI is more realistic actually. UIKit, much tougher (more mature, more tied to the IOS ecosystem).

Highly doubt it, Safari on Windows ran on AppKit and that thing is from the early 1990s. You'd be surprised how high level UIKit actually is.

Source?

Don’t have links, but it’s true. iTunes for Windows also includes chunks of AppKit.

The Windows ports of AppKit in both likely trace their lineages back to Yellow Box, which was the Windows port of AppKit that Apple briefly made available prior to the release of OS X 10.0.

My understanding was Foundation and bits of CoreGraphics but not AppKit. Yellow Box required DPS.