This document discusses .NET MAUI, a new multi-platform app UI framework from Microsoft that allows building mobile apps for Android, iOS, macOS and Windows using C# and .NET. It notes that .NET MAUI combines Xamarin.Forms and Windows Presentation Foundation into a single codebase and supports building apps directly from the command line using commands like `dotnet new maui` to generate a new multi-platform app project. The document also includes mentions of Uno Platform and Blazor Bindings as alternative multi-platform options.