Windows 8 has got a new handy context menu which is invoked by pressing Windows + X or by right-clicking the lower-left corner of the desktop:

Strangely enough, it's practically impossible to find any official documentation about it or even what it's called. A couple of third-party sites mention this menu as Win + X menu or Windows Tool Menu, but googling these terms leads to nothing.
What's this menu called? Is there any official info on this feature?