/usr/lib/ is in qtmultimedia5-dev 5.5.1-4ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5Multimedia.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5MultimediaWidgets.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5MultimediaQuick_p.pc
/usr/lib/x86_64-linux-gnu/cmake/
/usr/lib/x86_64-linux-gnu/cmake/Qt5MultimediaWidgets/
/usr/lib/x86_64-linux-gnu/cmake/Qt5MultimediaWidgets/Qt5MultimediaWidgetsConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5MultimediaWidgets/Qt5MultimediaWidgetsConfig.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5Multimedia/
/usr/lib/x86_64-linux-gnu/cmake/Qt5Multimedia/Qt5MultimediaConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5Multimedia/Qt5MultimediaConfig.cmake
/usr/lib/x86_64-linux-gnu/libQt5MultimediaWidgets.prl
/usr/lib/x86_64-linux-gnu/libQt5MultimediaQuick_p.prl
/usr/lib/x86_64-linux-gnu/libqgsttools_p.prl
/usr/lib/x86_64-linux-gnu/libQt5Multimedia.prl
/usr/lib/x86_64-linux-gnu/qt5/
/usr/lib/x86_64-linux-gnu/qt5/mkspecs/
/usr/lib/x86_64-linux-gnu/qt5/mkspecs/modules/
/usr/lib/x86_64-linux-gnu/qt5/mkspecs/modules/qt_lib_multimediawidgets.pri
/usr/lib/x86_64-linux-gnu/qt5/mkspecs/modules/qt_lib_multimedia.pri
/usr/lib/x86_64-linux-gnu/libQt5MultimediaQuick_p.so
/usr/lib/x86_64-linux-gnu/libQt5Multimedia.so
/usr/lib/x86_64-linux-gnu/libQt5MultimediaWidgets.so
/usr/lib/x86_64-linux-gnu/libqgsttools_p.so