/usr/lib/ is in libqt5gstreamer-dev 1.2.0-4.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/cmake/
/usr/lib/x86_64-linux-gnu/cmake/Qt5GStreamer/
/usr/lib/x86_64-linux-gnu/cmake/Qt5GStreamer/Qt5GStreamerConfig.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5GStreamer/Qt5GStreamerConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5GStreamer/Qt5GStreamerTargets-relwithdebinfo.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5GStreamer/Qt5GStreamerTargets.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5GStreamer/QtGStreamerConfigCommon.cmake
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5GLib-2.0.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5GStreamer-1.0.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5GStreamerQuick-1.0.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5GStreamerUi-1.0.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5GStreamerUtils-1.0.pc
/usr/lib/x86_64-linux-gnu/libQt5GLib-2.0.so
/usr/lib/x86_64-linux-gnu/libQt5GStreamer-1.0.so
/usr/lib/x86_64-linux-gnu/libQt5GStreamerQuick-1.0.so
/usr/lib/x86_64-linux-gnu/libQt5GStreamerUi-1.0.so
/usr/lib/x86_64-linux-gnu/libQt5GStreamerUtils-1.0.so