/usr/include/CGAL/Kernel_d/ is in libcgal-dev 4.2-5ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/CGAL/Kernel_d/Aff_transformationCd.h
/usr/include/CGAL/Kernel_d/Aff_transformationHd.h
/usr/include/CGAL/Kernel_d/Aff_transformation_d.h
/usr/include/CGAL/Kernel_d/Cartesian_const_iterator_d.h
/usr/include/CGAL/Kernel_d/DirectionCd.h
/usr/include/CGAL/Kernel_d/DirectionCd_impl.h
/usr/include/CGAL/Kernel_d/DirectionHd.h
/usr/include/CGAL/Kernel_d/DirectionHd_impl.h
/usr/include/CGAL/Kernel_d/Direction_d.h
/usr/include/CGAL/Kernel_d/HyperplaneCd.h
/usr/include/CGAL/Kernel_d/HyperplaneCd_impl.h
/usr/include/CGAL/Kernel_d/HyperplaneHd.h
/usr/include/CGAL/Kernel_d/HyperplaneHd_impl.h
/usr/include/CGAL/Kernel_d/Hyperplane_d.h
/usr/include/CGAL/Kernel_d/Interface_classes.h
/usr/include/CGAL/Kernel_d/Iso_box_d.h
/usr/include/CGAL/Kernel_d/Kernel_classesCd.h
/usr/include/CGAL/Kernel_d/Kernel_classesHd.h
/usr/include/CGAL/Kernel_d/Line_d.h
/usr/include/CGAL/Kernel_d/Line_d_impl.h
/usr/include/CGAL/Kernel_d/Linear_algebraCd_impl.h
/usr/include/CGAL/Kernel_d/Linear_algebraHd_impl.h
/usr/include/CGAL/Kernel_d/Matrix__.h
/usr/include/CGAL/Kernel_d/PVDHACd_impl.h
/usr/include/CGAL/Kernel_d/PVDHAHd_impl.h
/usr/include/CGAL/Kernel_d/Pair_d.h
/usr/include/CGAL/Kernel_d/PointCd.h
/usr/include/CGAL/Kernel_d/PointCd_impl.h
/usr/include/CGAL/Kernel_d/PointHd.h
/usr/include/CGAL/Kernel_d/PointHd_impl.h
/usr/include/CGAL/Kernel_d/Point_d.h
/usr/include/CGAL/Kernel_d/Ray_d.h
/usr/include/CGAL/Kernel_d/Segment_d.h
/usr/include/CGAL/Kernel_d/Sphere_d.h
/usr/include/CGAL/Kernel_d/Tuple_d.h
/usr/include/CGAL/Kernel_d/VectorCd.h
/usr/include/CGAL/Kernel_d/VectorCd_impl.h
/usr/include/CGAL/Kernel_d/VectorHd.h
/usr/include/CGAL/Kernel_d/VectorHd_impl.h
/usr/include/CGAL/Kernel_d/Vector__.h
/usr/include/CGAL/Kernel_d/Vector_d.h
/usr/include/CGAL/Kernel_d/debug.h
/usr/include/CGAL/Kernel_d/function_objects.h
/usr/include/CGAL/Kernel_d/function_objectsCd.h
/usr/include/CGAL/Kernel_d/function_objectsHd.h
/usr/include/CGAL/Kernel_d/intersection_objectsCd.h
/usr/include/CGAL/Kernel_d/intersection_objectsHd.h
/usr/include/CGAL/Kernel_d/intersection_objects_d.h
/usr/include/CGAL/Kernel_d/simple_objects.h