lxqt-qt6plugin provides the library libqtlxqt to integrate Qt with LXQt.
With this plugin, all Qt-based programs can adopt settings of LXQt,
such as the icon theme.

To integrate Qt with LXQt, export the following environment variable:
QT_QPA_PLATFORMTHEME=lxqt

This lxqt-qt6plugin SlackBuild provides qt6 support. For qt5 support,
please install lxqt-qtplugin.
Both lxqt-qtplugin and lxqt-qt6plugin may be installed on the same
system.