(Same on both 42.3 and 15.0) # zypper se -s qt | grep -i gtk | qtcurve-gtk2 | package | 1.8.19~git20150303-4.2 | x86_64 | OSS i+ | trinity-gtk-qt-engine| package | 2:0.8-14.0.4_1.oss423 | x86_64 | TDE i+ | trinity-gtk3-tqt-engine| package | 2:0.5-14.0.4_1.oss423 | x86_64 | TDE

TCC > GTK Styles & Fonts > GTK2 Styles:

WARNING: The Gtk-Qt theme engine is not installed. This means you will not be able to use your TDE style in GTK2 applications.

Exactly what package is this warning referring to?