As in
“We’ve finished taking all we need from the Mono project and implemented it into our proprietary .NET implementation for Linux, Android and iOS. Instead of getting flack for killing off Mono (which is open source and would’ve been forked anyways) we graciously give this old husk to the Wine project. We recommend that active Mono users and maintainers of Mono-based app frameworks migrate to .NET. kthnxbye!”
Good thing that it went to Wine I guess, as they do lots of work to get old Windows programs up and running in Linux and that often involves Mono.