/usr/include/ is in libkf5gravatar-dev 4:16.04.2-2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/KF5/
/usr/include/KF5/Gravatar/
/usr/include/KF5/Gravatar/GravatarCache
/usr/include/KF5/Gravatar/GravatarConfigWidget
/usr/include/KF5/Gravatar/GravatarConfigureSettingsDialog
/usr/include/KF5/Gravatar/GravatarDownloadPixmapWidget
/usr/include/KF5/Gravatar/GravatarResolvUrlJob
/usr/include/KF5/gravatar/
/usr/include/KF5/gravatar/gravatar_export.h
/usr/include/KF5/gravatar/gravatarcache.h
/usr/include/KF5/gravatar/gravatarconfiguresettingsdialog.h
/usr/include/KF5/gravatar/gravatarconfigwidget.h
/usr/include/KF5/gravatar/gravatardownloadpixmapwidget.h
/usr/include/KF5/gravatar/gravatarresolvurljob.h
/usr/include/KF5/gravatar/gravatarsettings.h
/usr/include/KF5/gravatar_version.h