This is just one Windows 9 concept in a long line of concepts
Fans have been making Windows 9 concepts for a while now but, somehow, most of the them take their cue from Linux systems.This is just the case with this Windows 9 concept, which in all fairness looks a lot better than anything that might come from Microsoft's hands.
The reason this concept looks so good is because it also looks very Linux-like. Linux systems are known to be highly configurable and all the elements of the interface can be changed, themed, and tweaked.
Just at a glance, the Windows 9 concept is full of KDE, GNOME, and Ubuntu (Unity) elements. You might also notice that the browser also has some elements from Nautilus.
By all means, this is not a bad thing. People should take inspiration from all the possible sources. As long as the finished product looks good and makes users happy, it's all for the better.
If you spot any other similarities, don't be shy and leave us a comment below.