/usr/include/ is in libkf5calendarsupport-dev 4:17.12.3-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/KF5/
/usr/include/KF5/CalendarSupport/
/usr/include/KF5/CalendarSupport/ArchiveDialog
/usr/include/KF5/CalendarSupport/CalPrintDefaultPlugins
/usr/include/KF5/CalendarSupport/CalPrintPluginBase
/usr/include/KF5/CalendarSupport/CalPrinter
/usr/include/KF5/CalendarSupport/CalendarSingleton
/usr/include/KF5/CalendarSupport/CategoryConfig
/usr/include/KF5/CalendarSupport/CategoryHierarchyReader
/usr/include/KF5/CalendarSupport/CellItem
/usr/include/KF5/CalendarSupport/CollectionSelection
/usr/include/KF5/CalendarSupport/EventArchiver
/usr/include/KF5/CalendarSupport/FreeBusyCalendar
/usr/include/KF5/CalendarSupport/FreeBusyItem
/usr/include/KF5/CalendarSupport/FreeBusyItemModel
/usr/include/KF5/CalendarSupport/FreePeriodModel
/usr/include/KF5/CalendarSupport/IdentityManager
/usr/include/KF5/CalendarSupport/IncidenceViewer
/usr/include/KF5/CalendarSupport/KCalPrefs
/usr/include/KF5/CalendarSupport/MessageWidget
/usr/include/KF5/CalendarSupport/Plugin
/usr/include/KF5/CalendarSupport/PrintPlugin
/usr/include/KF5/CalendarSupport/Utils
/usr/include/KF5/calendarsupport/
/usr/include/KF5/calendarsupport/archivedialog.h
/usr/include/KF5/calendarsupport/calendarsingleton.h
/usr/include/KF5/calendarsupport/calendarsupport_export.h
/usr/include/KF5/calendarsupport/calprintdefaultplugins.h
/usr/include/KF5/calendarsupport/calprinter.h
/usr/include/KF5/calendarsupport/calprintpluginbase.h
/usr/include/KF5/calendarsupport/categoryconfig.h
/usr/include/KF5/calendarsupport/categoryhierarchyreader.h
/usr/include/KF5/calendarsupport/cellitem.h
/usr/include/KF5/calendarsupport/collectionselection.h
/usr/include/KF5/calendarsupport/eventarchiver.h
/usr/include/KF5/calendarsupport/freebusycalendar.h
/usr/include/KF5/calendarsupport/freebusyitem.h
/usr/include/KF5/calendarsupport/freebusyitemmodel.h
/usr/include/KF5/calendarsupport/freeperiodmodel.h
/usr/include/KF5/calendarsupport/identitymanager.h
/usr/include/KF5/calendarsupport/incidenceviewer.h
/usr/include/KF5/calendarsupport/kcalprefs.h
/usr/include/KF5/calendarsupport/kcalprefs_base.h
/usr/include/KF5/calendarsupport/messagewidget.h
/usr/include/KF5/calendarsupport/plugin.h
/usr/include/KF5/calendarsupport/printplugin.h
/usr/include/KF5/calendarsupport/ui_calprintdayconfig_base.h
/usr/include/KF5/calendarsupport/ui_calprintincidenceconfig_base.h
/usr/include/KF5/calendarsupport/ui_calprintmonthconfig_base.h
/usr/include/KF5/calendarsupport/ui_calprinttodoconfig_base.h
/usr/include/KF5/calendarsupport/ui_calprintweekconfig_base.h
/usr/include/KF5/calendarsupport/utils.h
/usr/include/KF5/calendarsupport_version.h