Look for gtk3_preview instead of gtk_preview
gtk3_preview was removed in 9323a96a9e7ec93f735e10ee671c3824b35429df in kde-gtk-config
parent
185a5245
gtk3_preview was removed in 9323a96a9e7ec93f735e10ee671c3824b35429df in kde-gtk-config
mentioned in commit 6fed05d4
·mentioned in commit 6fed05d4