A way for Win32 projects to use WinUI3. Article about: https://www.codeproject.com/Articles/5359576/WinUI3-in-existing-Win32-applications
The WinUI3 app is an 'unpackaged' Desktop App with one hidden window; It displays/hides subelements (StackPanels) on request from the Win32 application My XML3 (https://github.com/WindowsNT/xml) library is used for communication (included in the repository)