/usr/include/ksysguard/ is in libkf5sysguard-dev 4:5.5.5-0ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ksysguard/ksgrd/
/usr/include/ksysguard/ksgrd/SensorAgent.h
/usr/include/ksysguard/ksgrd/SensorClient.h
/usr/include/ksysguard/ksgrd/SensorManager.h
/usr/include/ksysguard/ksgrd/SensorShellAgent.h
/usr/include/ksysguard/ksgrd/SensorSocketAgent.h
/usr/include/ksysguard/ksignalplotter.h
/usr/include/ksysguard/lsof.h
/usr/include/ksysguard/processcore/
/usr/include/ksysguard/processcore/process.h
/usr/include/ksysguard/processcore/processes.h
/usr/include/ksysguard/processui/
/usr/include/ksysguard/processui/KTextEditVT.h
/usr/include/ksysguard/processui/ProcessFilter.h
/usr/include/ksysguard/processui/ProcessModel.h
/usr/include/ksysguard/processui/ksysguardprocesslist.h