/usr/include/CGAL/RS/ is in libcgal-dev 4.2-5ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/CGAL/RS/Algebraic_kernel_rs_1.h
/usr/include/CGAL/RS/algebraic_1.h
/usr/include/CGAL/RS/algebraic_1_comparisons.h
/usr/include/CGAL/RS/algebraic_1_constructors.h
/usr/include/CGAL/RS/algebraic_1_member.h
/usr/include/CGAL/RS/algebraic_1_operators.h
/usr/include/CGAL/RS/algebraic_1_other.h
/usr/include/CGAL/RS/algebraic_1_real_embeddable.h
/usr/include/CGAL/RS/basic.h
/usr/include/CGAL/RS/compare_1.h
/usr/include/CGAL/RS/dyadic.h
/usr/include/CGAL/RS/functors_1.h
/usr/include/CGAL/RS/isolator_1.h
/usr/include/CGAL/RS/isole_1.h
/usr/include/CGAL/RS/polynomial_1.h
/usr/include/CGAL/RS/polynomial_1_constructors.h
/usr/include/CGAL/RS/polynomial_1_eval.h
/usr/include/CGAL/RS/polynomial_1_functors.h
/usr/include/CGAL/RS/polynomial_1_impl.h
/usr/include/CGAL/RS/polynomial_1_io.h
/usr/include/CGAL/RS/polynomial_1_member.h
/usr/include/CGAL/RS/polynomial_1_operators.h
/usr/include/CGAL/RS/polynomial_1_parser.h
/usr/include/CGAL/RS/polynomial_1_utils.h
/usr/include/CGAL/RS/polynomial_converter.h
/usr/include/CGAL/RS/refine_1_rs.h
/usr/include/CGAL/RS/rs_calls_1.h
/usr/include/CGAL/RS/sign_1.h
/usr/include/CGAL/RS/sign_1_no_rs.h
/usr/include/CGAL/RS/sign_1_rs.h
/usr/include/CGAL/RS/solve_1.h
/usr/include/CGAL/RS/ugcd/
/usr/include/CGAL/RS/ugcd/crt.h
/usr/include/CGAL/RS/ugcd/inverse.h
/usr/include/CGAL/RS/ugcd/p.h
/usr/include/CGAL/RS/ugcd/pagealloc.h
/usr/include/CGAL/RS/ugcd/pp.h
/usr/include/CGAL/RS/ugcd/primes.h
/usr/include/CGAL/RS/ugcd/ugcd.h