/usr/include/KF5/KBookmarks/ is in libkf5bookmarks-dev 5.18.0-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/KF5/KBookmarks/KBookmark
/usr/include/KF5/KBookmarks/KBookmarkAction
/usr/include/KF5/KBookmarks/KBookmarkActionInterface
/usr/include/KF5/KBookmarks/KBookmarkActionMenu
/usr/include/KF5/KBookmarks/KBookmarkContextMenu
/usr/include/KF5/KBookmarks/KBookmarkDialog
/usr/include/KF5/KBookmarks/KBookmarkDomBuilder
/usr/include/KF5/KBookmarks/KBookmarkManager
/usr/include/KF5/KBookmarks/KBookmarkMenu
/usr/include/KF5/KBookmarks/KBookmarkOwner
/usr/include/KF5/KBookmarks/KonqBookmarkMenu
/usr/include/KF5/KBookmarks/kbookmark.h
/usr/include/KF5/KBookmarks/kbookmarkaction.h
/usr/include/KF5/KBookmarks/kbookmarkactioninterface.h
/usr/include/KF5/KBookmarks/kbookmarkactionmenu.h
/usr/include/KF5/KBookmarks/kbookmarkcontextmenu.h
/usr/include/KF5/KBookmarks/kbookmarkdialog.h
/usr/include/KF5/KBookmarks/kbookmarkdombuilder.h
/usr/include/KF5/KBookmarks/kbookmarkexporter.h
/usr/include/KF5/KBookmarks/kbookmarkimporter.h
/usr/include/KF5/KBookmarks/kbookmarkimporter_ie.h
/usr/include/KF5/KBookmarks/kbookmarkimporter_ns.h
/usr/include/KF5/KBookmarks/kbookmarkimporter_opera.h
/usr/include/KF5/KBookmarks/kbookmarkmanager.h
/usr/include/KF5/KBookmarks/kbookmarkmenu.h
/usr/include/KF5/KBookmarks/kbookmarkowner.h
/usr/include/KF5/KBookmarks/kbookmarks_export.h
/usr/include/KF5/KBookmarks/konqbookmarkmenu.h