/usr/include/x86_64-linux-gnu/ is in liboxideqtquick-dev 1.13.6-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/x86_64-linux-gnu/oxide-qt/
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquickglobal.h
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquicklocationbarcontroller.h
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquickscriptmessage.h
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquickscriptmessagehandler.h
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquickscriptmessagerequest.h
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquicktouchselectioncontroller.h
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquickuserscript.h
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquickwebcontext.h
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquickwebframe.h
/usr/include/x86_64-linux-gnu/oxide-qt/OxideQtQuick/oxideqquickwebview.h