qt5-gtk-platformtheme 5.15.8+dfsg-2build1 (riscv64 binary) in ubuntu lunar

 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 provides the GTK+ 3 platform theme, which makes Qt use
 native icon themes, fonts, and dialogs on GTK-based environments.