Within what development environment is XAML most commonly used?

XAML and .NET: XAML (eXtensible Application Markup Language) is primarily used within the .NET framework for defining user interfaces. Specifically, technologies like:

WPF (Windows Presentation Foundation): Desktop application UIs

Xamarin: Mobile app UIs

XAML in Other Frameworks: While some limited adaptation exists, its core use is tightly coupled with .NET technologies.