.... i believe the list is the X11 rgb.txt on linux anyways ..... you might ask on the Perl/Gtk2 maillist for a definitive answer..... the closest thing i see is "perldoc Gtk2::Gdk::Colormap"..... where you can define your own map if you want

...as far as a special Goo map of colors..... i think as a compliant Gtk2 widget.....it will use whatever your other Gtk2 widgets have available.... one big happy family :-)