https://bugs.winehq.org/show_bug.cgi?id=24501
--- Comment #17 from Vincent Povirk madewokherd@gmail.com --- It seems they're dumping all the code at once: https://github.com/dotnet/wpf/pull/720
It does indeed contain Managed C++ code, which is a challenge.
The next step for us will be to build this on Windows with the appropriate versioning, and try to get it running in Wine Mono.
Once it works, we can build it as a separate package, then think about how to remove the Windows build dependency so it can go in Wine Mono. The amount of Managed C++ code is relatively small, so we can probably work something out.