/usr/include/CGAL/Surface_mesher/ is in libcgal-dev 4.2-5ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/CGAL/Surface_mesher/Combining_oracle.h
/usr/include/CGAL/Surface_mesher/Has_edges.h
/usr/include/CGAL/Surface_mesher/Implicit_surface_oracle_3.h
/usr/include/CGAL/Surface_mesher/Intersection_data_structure_3.h
/usr/include/CGAL/Surface_mesher/Null_oracle_visitor.h
/usr/include/CGAL/Surface_mesher/Point_surface_indices_oracle_visitor.h
/usr/include/CGAL/Surface_mesher/Poisson_implicit_surface_oracle_3.h
/usr/include/CGAL/Surface_mesher/Polyhedral_oracle.h
/usr/include/CGAL/Surface_mesher/Profile_counter.h
/usr/include/CGAL/Surface_mesher/Profile_timer.h
/usr/include/CGAL/Surface_mesher/Sphere_oracle_3.h
/usr/include/CGAL/Surface_mesher/Standard_criteria.h
/usr/include/CGAL/Surface_mesher/Surface_mesher.h
/usr/include/CGAL/Surface_mesher/Surface_mesher_edges_level.h
/usr/include/CGAL/Surface_mesher/Surface_mesher_edges_level_visitor.h
/usr/include/CGAL/Surface_mesher/Surface_mesher_manifold.h
/usr/include/CGAL/Surface_mesher/Surface_mesher_regular_edges.h
/usr/include/CGAL/Surface_mesher/Surface_mesher_visitor.h
/usr/include/CGAL/Surface_mesher/Types_generators.h
/usr/include/CGAL/Surface_mesher/Verbose_flag.h
/usr/include/CGAL/Surface_mesher/Vertices_on_the_same_psc_element_criterion.h
/usr/include/CGAL/Surface_mesher/Vertices_on_the_same_surface_criterion.h