qt4-default - 4:4.8.7+dfsg-18+deb10u1 main

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 sets Qt 4 to be the default Qt version to be used when
using development binaries like qmake. It provides a default
configuration for qtchooser, but does not prevent alternative Qt
installations from being used.
.
This package should not be used for building Debian packages. Take a
look at http://pkg-kde.alioth.debian.org/packagingqtstuff.html for
more information.