/usr/include/KF5/KConfigWidgets/ is in libkf5configwidgets-dev 5.18.0-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/KF5/KConfigWidgets/KCModule
/usr/include/KF5/KConfigWidgets/KCodecAction
/usr/include/KF5/KConfigWidgets/KColorScheme
/usr/include/KF5/KConfigWidgets/KColorSchemeManager
/usr/include/KF5/KConfigWidgets/KConfigDialog
/usr/include/KF5/KConfigWidgets/KConfigDialogManager
/usr/include/KF5/KConfigWidgets/KConfigViewStateSaver
/usr/include/KF5/KConfigWidgets/KHelpClient
/usr/include/KF5/KConfigWidgets/KLanguageButton
/usr/include/KF5/KConfigWidgets/KPasteTextAction
/usr/include/KF5/KConfigWidgets/KRecentFilesAction
/usr/include/KF5/KConfigWidgets/KStandardAction
/usr/include/KF5/KConfigWidgets/KTipDialog
/usr/include/KF5/KConfigWidgets/KViewStateMaintainer
/usr/include/KF5/KConfigWidgets/kcmodule.h
/usr/include/KF5/KConfigWidgets/kcodecaction.h
/usr/include/KF5/KConfigWidgets/kcolorscheme.h
/usr/include/KF5/KConfigWidgets/kcolorschememanager.h
/usr/include/KF5/KConfigWidgets/kconfigdialog.h
/usr/include/KF5/KConfigWidgets/kconfigdialogmanager.h
/usr/include/KF5/KConfigWidgets/kconfigviewstatesaver.h
/usr/include/KF5/KConfigWidgets/kconfigwidgets_export.h
/usr/include/KF5/KConfigWidgets/khelpclient.h
/usr/include/KF5/KConfigWidgets/klanguagebutton.h
/usr/include/KF5/KConfigWidgets/kpastetextaction.h
/usr/include/KF5/KConfigWidgets/krecentfilesaction.h
/usr/include/KF5/KConfigWidgets/kstandardaction.h
/usr/include/KF5/KConfigWidgets/ktip.h
/usr/include/KF5/KConfigWidgets/ktipdialog.h
/usr/include/KF5/KConfigWidgets/kviewstatemaintainer.h