One one hand it makes sense they copied -- why spend time and effort into drawing all those assets from scratch? Take the best out there, steal it and you are done.

On the other and Apple is the epitome of your capitalist, western, company -- one that would surely be decried as a failure or an example of Western evil decadence by the propaganda. Perhaps those developing this are sort of things are given a more free reign and operate outside the "propaganda" domain.

Finder, Calculator, Calendar, the top menu, etc. All really spot on.

I'm playing around in it still. Managed to find my way to the Terminal, and I'm poking around the filesystem.

It is Linux, and seems to be based on a stripped-down version of RedHat (going from some of the remnants of certain man pages).

The UI is a modified/themed KDE.

They did a really good job with the apps - for example, the calculator app is "Calculator.app", which is really a directory with a Contents/Resources, etc directories inside it; the same way OS X does it.