/usr/lib/x86_64-linux-gnu/ is in libqt5webkit5-dev 5.5.1+dfsg-2ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/libQt5WebKitWidgets.prl
/usr/lib/x86_64-linux-gnu/cmake/
/usr/lib/x86_64-linux-gnu/cmake/Qt5WebKitWidgets/
/usr/lib/x86_64-linux-gnu/cmake/Qt5WebKitWidgets/Qt5WebKitWidgetsConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5WebKitWidgets/Qt5WebKitWidgetsConfig.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5WebKit/
/usr/lib/x86_64-linux-gnu/cmake/Qt5WebKit/Qt5WebKitConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/Qt5WebKit/Qt5WebKitConfig.cmake
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5WebKit.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/Qt5WebKitWidgets.pc
/usr/lib/x86_64-linux-gnu/libQt5WebKit.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_webkit.pri
/usr/lib/x86_64-linux-gnu/qt5/mkspecs/modules/qt_lib_webkitwidgets.pri
/usr/lib/x86_64-linux-gnu/libQt5WebKitWidgets.so
/usr/lib/x86_64-linux-gnu/libQt5WebKit.so