/usr/include/CGAL/Sweep_line_2/ is in libcgal-dev 4.2-5ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/CGAL/Sweep_line_2/Arr_basic_insertion_sl_visitor.h
/usr/include/CGAL/Sweep_line_2/Arr_basic_insertion_traits_2.h
/usr/include/CGAL/Sweep_line_2/Arr_batched_pl_sl_visitor.h
/usr/include/CGAL/Sweep_line_2/Arr_construction_event.h
/usr/include/CGAL/Sweep_line_2/Arr_construction_sl_visitor.h
/usr/include/CGAL/Sweep_line_2/Arr_construction_subcurve.h
/usr/include/CGAL/Sweep_line_2/Arr_default_overlay_traits_base.h
/usr/include/CGAL/Sweep_line_2/Arr_insertion_sl_visitor.h
/usr/include/CGAL/Sweep_line_2/Arr_insertion_traits_2.h
/usr/include/CGAL/Sweep_line_2/Arr_overlay_sl_visitor.h
/usr/include/CGAL/Sweep_line_2/Arr_overlay_subcurve.h
/usr/include/CGAL/Sweep_line_2/Arr_overlay_traits_2.h
/usr/include/CGAL/Sweep_line_2/Arr_vert_decomp_sl_visitor.h
/usr/include/CGAL/Sweep_line_2/Basic_sweep_line_2_impl.h
/usr/include/CGAL/Sweep_line_2/Sweep_line_2_debug.h
/usr/include/CGAL/Sweep_line_2/Sweep_line_2_impl.h
/usr/include/CGAL/Sweep_line_2/Sweep_line_2_utils.h
/usr/include/CGAL/Sweep_line_2/Sweep_line_2_visitors.h
/usr/include/CGAL/Sweep_line_2/Sweep_line_curve_pair.h
/usr/include/CGAL/Sweep_line_2/Sweep_line_event.h
/usr/include/CGAL/Sweep_line_2/Sweep_line_functors.h
/usr/include/CGAL/Sweep_line_2/Sweep_line_subcurve.h