There has been some confusion about it, since the “start menu” bar looks very windows/KDE-ish, but it is in fact XFCE underneath, and the Thunar file manager….
On the developer section of their site Zonbu lists some other favorite projects:
“A few projects we really like:
This includes Gentoo, Xfce (including Thunar), Gnome, OpenOffice.org, Evolution, openChrome, MPlayer, MPlayerplug-in, Banshee, F-Spot, and Pigdin. We have sponsored some of those projects in the past few months and we welcome your participation in their further development.”