Neutrino is for people who work for long and want to get the most of their computers. There is no colours used for window decoration (except the Close button, which is considered dangerous), no unnecessary transparency. The active window is clearly distinguished by a dark contrast border, others have easily readable titles, even if their opacity is reduced.
There were also Above, Shade and Stick buttons added, which can be very useful sometimes. The buttons on inactive windows become more contrast when the mouse is hovering above them (the Max button on Calculator – Advanced in the screenshot).
The proposed widget theme is Murrine-Neutrino.