With two clicks to the same project you would've hit a big fat "PROJECT START" thread, which clearly lists it as being linux based.
Extracted from Announcement SCALE is an exciting new addition to the TrueNAS software family. It uses much of the same TrueNAS 12.0 source code, but adds a few different twists. For those eager to know more about the the goals of the SCALE project, they are defined by this acronym: Scale-out...
www.truenas.com
Same with google, which you already found.
To be frank: If you have trouble finding information that is
this accessable, I have some doubts if using all sorts of (not-very-standard) virtualisation software is a great plan to begin with.
You can test it with whatever you like ofcoarse, but there are no official or semi-official guides or images for vagrant installs afaik.