The newest part of this is the new Gmail interface. Here is it:
|New interface! (Click to enlarge)|
You can test this design by clicking the button -> Mail Settings -> Themes -> Preview (Dense).
I think it's a pretty new design, that has never been seen before. I like it ;).
The first thing I spotted (technically) that when I scroll down the page the "archive" "spam" "delete" "important" "not important"... bar comes with the page. It's quite useful, because you don't have to scroll up to "take action" with the message.
Overall there are only changes in the colors and shapes.