All of the following icons are not part of Emacs, but distributed and
used by Emacs.
The following icons are from GTK+ 2.x:
close.xpm copy.xpm cut.xpm help.xpm home.xpm
index.xpm jump-to.xpm left-arrow.xpm new.xpm open.xpm
paste.xpm preferences.xpm print.xpm right-arrow.xpm save.xpm
saveas.xpm search.xpm spell.xpm undo.xpm up-arrow.xpm
back-arrow.xpm and fwd-arrow.xpm are slightly modified undo and redo.
diropen.xpm is file-manager.png from Gnome hicolor theme.
The following icons are from GNOME 2.10:
refresh.pbm, refresh.xpm
