[gentoo-user] meaning of (-clutter) in an emerge USE list

[Allan Gottlieb]

In /etc/portage/package.use I have

    # Need these or for some games
    gnome-extra/gnome-games         clutter opengl

But when I try to emerge gnome-games, I don't get clutter

   [ebuild   R   ] gnome-extra/gnome-games-2.30.2-r1  USE="guile opengl 
-artworkextra (-clutter) -test" 0 kB

I know that the (-clutter) means that the clutter flag has been removed,
but I can't see why it is removed.  Indeed the ebuild specifically warns
me that disabling clutter means certain games are not built.

thanks,
allan