qt5-gtk2-platformtheme 5.0.0+git23.g335dbec-3ubuntu1 (amd64 binary) in ubuntu eoan

 Qt is a cross-platform C++ application framework. Qt's primary feature
 is its rich set of widgets that provide standard GUI functionality.
 .
 This package contains the GTK+ 2 style and platform theme. Export
 QT_QPA_PLATFORMTHEME=gtk2 to enable it for all Qt applications.