/usr/include/ is in libqt5waylandclient5-dev 5.9.5-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/x86_64-linux-gnu/
/usr/include/x86_64-linux-gnu/qt5/
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/5.9.5/
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/5.9.5/QtWaylandClient/
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/QWaylandClientExtension
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/QWaylandClientExtensionTemplate
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/QtWaylandClient
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/QtWaylandClientDepends
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/QtWaylandClientVersion
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/qtwaylandclient-config.h
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/qtwaylandclientglobal.h
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/qtwaylandclientversion.h
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/qwaylandclientexport.h
/usr/include/x86_64-linux-gnu/qt5/QtWaylandClient/qwaylandclientextension.h