This is a set of widget styles for Gtk2 based apps. The fonts and colours for the GTK themes will be read in from your Qt settings so any KDE font/colour changes will also affect your GTK apps. If you want Gtk2 apps to use the theme system wide, create a symbolic link to the new theme like this: ln -s /usr/share/themes/QtCurve/gtk-2.0/gtkrc /etc/gtk-2.0/gtkrc If you are using a dark theme, and fonts in Firefox are unreadable because it does not invert the colors, you can pass USERCHROME=no to the script, which will disable the modification of userchrome.css in Firefox.