They ported an old dotnet
It’s an old version, but even today you can still make new apps that use it, using modern development tools (the latest version of Visual Studio). It’s missing a large number of newer features, but all the essential stuff is available.
I still maintain software written in dotnet compact for windows CE 💀 limited to VS2008 though
Wow I totally forgot about the compact version. I wrote a few C# apps for Windows Mobile using the compact framework and it worked pretty well. I posted some to XDA-Developers too (e.g. https://xdaforums.com/t/app-htcbutton-beta-change-function-of-wired-headset-button-skip-songs-via-button.492947/ ).
Port to Linux next ◉‿◉
This is like a movie, very good especially for this subject