Well, XAML itself doesn't have anything to do with UI, it's just a serialization of an object graph with hints about code generation. There's AvaloniaUI, thoug

Well, XAML itself doesn't have anything to do with UI, it's just a serialization of an object graph with hints about code generation. There's AvaloniaUI, though, if you're looking for XAML, UI, and cross-platform.