As WSL is becoming a critical piece of Microsoft’s cloud and data-center audience, openSUSE is working on technologies that help developers use distributions of their choice for WSL. Users can run the same WSL distribution that they run in the cloud or on their servers.
The core piece of openSUSE’s WSL offering is the WSL appx files, which are basically zip files that contain a tarball of a Linux system (like a container) and a Windows exe file, the so called launcher.
An openSUSE blog explains[1] that “building a container is something OBS can already do fully automatic by means of Kiwi. The launcher as well as the final appx however is typically built on a Windows machine using Visual Studio by the developer.”
As a result of this work, OBS can actually build the WSL appx from sources. Anyone can build their WSL distribution. However, since the files are signed by openSUSE and not Microsoft, you will need additional steps to run them on Windows 10 machines.