view all windows in Mavericks keyboard shortcut
I am pretty sure this feature is called "Application Windows". If you go to System Settings -> Mission Control, in the bottom section is a list of four items you can attach to keyboard shortcuts. This feature is called "Application windows" in that list.

Additionally, you can enable a Hot Corner for it: Click the Hot Corners button in the bottom left of the Mission Control settings; you should be able to specify a special action for moving your mouse into each corner of your screen. This feature is called "Application Windows" in the list of options.