/usr/include/ is in libkf5kdgantt2-dev 4:16.04.2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/KF5/
/usr/include/KF5/KDGantt2/
/usr/include/KF5/KDGantt2/KDGanttAbstractGrid
/usr/include/KF5/KDGantt2/KDGanttAbstractRowController
/usr/include/KF5/KDGantt2/KDGanttConstraint
/usr/include/KF5/KDGantt2/KDGanttDateTimeGrid
/usr/include/KF5/KDGantt2/KDGanttGlobal
/usr/include/KF5/KDGantt2/KDGanttGraphicsItem
/usr/include/KF5/KDGantt2/KDGanttGraphicsView
/usr/include/KF5/KDGantt2/KDGanttItemDelegate
/usr/include/KF5/KDGantt2/KDGanttStyleOptionGanttItem
/usr/include/KF5/KDGantt2/KDGanttView
/usr/include/KF5/kdgantt2/
/usr/include/KF5/kdgantt2/kdgantt_export.h
/usr/include/KF5/kdgantt2/kdganttabstractgrid.h
/usr/include/KF5/kdgantt2/kdganttabstractrowcontroller.h
/usr/include/KF5/kdgantt2/kdganttconstraint.h
/usr/include/KF5/kdgantt2/kdganttdatetimegrid.h
/usr/include/KF5/kdgantt2/kdganttglobal.h
/usr/include/KF5/kdgantt2/kdganttgraphicsitem.h
/usr/include/KF5/kdgantt2/kdganttgraphicsview.h
/usr/include/KF5/kdgantt2/kdganttitemdelegate.h
/usr/include/KF5/kdgantt2/kdganttstyleoptionganttitem.h
/usr/include/KF5/kdgantt2/kdganttview.h
/usr/include/KF5/kdgantt2_version.h