C++/WinRT Native XAML Library (2019 demo)

Question

I've now watched this C++/WinRT XAML demo several times -- dated May 7, 2019:

https://www.youtube.com/watch?v=X41j_gzSwOY&feature=youtu.be

especially stepping through between 44:20 - 53:53. Is that stuff still experimental? It's referenced from the top of a page on "Introduction to C++/WinRT"

https://learn.microsoft.com/en-us/windows/uwp/cpp-and-winrt-apis/intro-to-using-cpp-with-winrt

I can find no definitions or documentation for several essential symbols in the example code: xaml_page, xaml_app, xaml_user_control, xaml_member. They're supposedly defined in "winrt/xaml.h", which the presenter quickly mentions is "experimental" and which still appears not to exist. I have <winrt/Windows.UI.Xaml.h>, but it does not define those symbols.

As one trying to learn and use C++/WinRT XAML, it's a little confusing and frustrating for the "Introduction" page to begin with a demonstration of features that aren't yet available.

Many of the examples I can find are still only in C#, or C++/CX, not C++/WinRT.

Any prediction for when the features demonstrated there will be released for consumption?

I'm currently running Visual Studio 2019, Windows 10 version 1909.

Thanks for any enlightenment.