Microsoft Announces Its Own Linux OS, on It's F.O.S.S., April 1, 2015.
I cannot find it on distrowatch. Was this a hoax, or is this a real, living distro that can be downloaded, tested?
Well, it was published on April 1, 2015 - April Fools' Day. They produce other jokes on April 1st, like Linus Torvalds To Join Microsoft To Head Windows 9 Project.
Microsoft Linux is a similar effort. The Overview on the home page states,
Microsoft Linux provides all the power of the Linux Operating System with the ease of use you’ve come to expect from Microsoft Products.
This is augmented with a list of features, pricing information, quotes from industry and government leaders, useful links, and news bites regarding other Microsoft projects.
Thanks to user80998 for posting this the first time.
It's not miux, it's Azure Cloud Switch, which is based on Linux!