/usr/include/KF5/ is in plasma-framework-dev 5.18.0-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/KF5/Plasma/
/usr/include/KF5/Plasma/Applet
/usr/include/KF5/Plasma/Containment
/usr/include/KF5/Plasma/ContainmentActions
/usr/include/KF5/Plasma/Corona
/usr/include/KF5/Plasma/DataContainer
/usr/include/KF5/Plasma/DataEngine
/usr/include/KF5/Plasma/DataEngineConsumer
/usr/include/KF5/Plasma/FrameSvg
/usr/include/KF5/Plasma/Package
/usr/include/KF5/Plasma/PackageStructure
/usr/include/KF5/Plasma/Plasma
/usr/include/KF5/Plasma/PluginLoader
/usr/include/KF5/Plasma/Service
/usr/include/KF5/Plasma/ServiceJob
/usr/include/KF5/Plasma/Svg
/usr/include/KF5/Plasma/Theme
/usr/include/KF5/plasma/
/usr/include/KF5/plasma/applet.h
/usr/include/KF5/plasma/containment.h
/usr/include/KF5/plasma/containmentactions.h
/usr/include/KF5/plasma/corona.h
/usr/include/KF5/plasma/datacontainer.h
/usr/include/KF5/plasma/dataengine.h
/usr/include/KF5/plasma/dataengineconsumer.h
/usr/include/KF5/plasma/framesvg.h
/usr/include/KF5/plasma/package.h
/usr/include/KF5/plasma/packagestructure.h
/usr/include/KF5/plasma/plasma.h
/usr/include/KF5/plasma/plasma_export.h
/usr/include/KF5/plasma/pluginloader.h
/usr/include/KF5/plasma/scripting/
/usr/include/KF5/plasma/scripting/appletscript.h
/usr/include/KF5/plasma/scripting/dataenginescript.h
/usr/include/KF5/plasma/scripting/scriptengine.h
/usr/include/KF5/plasma/service.h
/usr/include/KF5/plasma/servicejob.h
/usr/include/KF5/plasma/svg.h
/usr/include/KF5/plasma/theme.h
/usr/include/KF5/plasma/version.h
/usr/include/KF5/plasma_version.h