Ruben Gomez spotted another test, this one is from Google, he posted about it on Twitter and called it material design for desktop. It looks like the card style design we reported about a few weeks ago.
But Ruben explained it is also visible on the home page and shared screen shots showing how the Google home page is gray in the new test design. It also has a bigger search box in the center.
Here is the new home page test in gray (click to enlarge):
Here is the current white home page (click to enlarge):
Ruben shared more examples as well as a video.
Forum discussion at Twitter.