Mono

The games-util/steam-games-meta package supports the mono use flag.

The use flag description goes as follows: "Build Mono bindings to support dotnet type stuff"

As a reference here is the Wikipedia article on mono: https://en.wikipedia.org/wiki/Mono_(software)

I am not sure this is the correct/best way to go about it, but I was wondering if we could use this wiki page to collect some more information on what one would need this use flag for.