/usr/include/CGAL/Polynomial/internal/Rational/ is in libcgal-dev 4.2-5ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/CGAL/Polynomial/internal/Rational/Are_negations.h
/usr/include/CGAL/Polynomial/internal/Rational/Bezier_root_counter.h
/usr/include/CGAL/Polynomial/internal/Rational/Compare_isolated_roots_in_interval.h
/usr/include/CGAL/Polynomial/internal/Rational/Construct_function.h
/usr/include/CGAL/Polynomial/internal/Rational/Derivative.h
/usr/include/CGAL/Polynomial/internal/Rational/Descartes_has_root.h
/usr/include/CGAL/Polynomial/internal/Rational/Descartes_root_counter.h
/usr/include/CGAL/Polynomial/internal/Rational/Euclidean_Sturm_sequence.h
/usr/include/CGAL/Polynomial/internal/Rational/Evaluate_polynomial.h
/usr/include/CGAL/Polynomial/internal/Rational/Invert_variable.h
/usr/include/CGAL/Polynomial/internal/Rational/Map_rational_interval_to_positive.h
/usr/include/CGAL/Polynomial/internal/Rational/Monic_Sturm_sequence.h
/usr/include/CGAL/Polynomial/internal/Rational/Negate_variable.h
/usr/include/CGAL/Polynomial/internal/Rational/Primitive_part_Sturm_sequence.h
/usr/include/CGAL/Polynomial/internal/Rational/Pseudo_quotient.h
/usr/include/CGAL/Polynomial/internal/Rational/Pseudo_remainder.h
/usr/include/CGAL/Polynomial/internal/Rational/Quotient.h
/usr/include/CGAL/Polynomial/internal/Rational/Quotient_remainder.h
/usr/include/CGAL/Polynomial/internal/Rational/Rational_multiplicity.h
/usr/include/CGAL/Polynomial/internal/Rational/Rational_traits_base.h
/usr/include/CGAL/Polynomial/internal/Rational/Rational_translate_zero.h
/usr/include/CGAL/Polynomial/internal/Rational/Reduced_Sturm_sequence.h
/usr/include/CGAL/Polynomial/internal/Rational/Remainder.h
/usr/include/CGAL/Polynomial/internal/Rational/Root_bound_evaluator.h
/usr/include/CGAL/Polynomial/internal/Rational/Shift_power.h
/usr/include/CGAL/Polynomial/internal/Rational/Sign_Sturm_sequence.h
/usr/include/CGAL/Polynomial/internal/Rational/Sign_above_rational.h
/usr/include/CGAL/Polynomial/internal/Rational/Sign_at_rational.h
/usr/include/CGAL/Polynomial/internal/Rational/Sign_below_rational.h
/usr/include/CGAL/Polynomial/internal/Rational/Standard_sequence.h
/usr/include/CGAL/Polynomial/internal/Rational/Sturm_root_counter.h
/usr/include/CGAL/Polynomial/internal/Rational/Sturm_sequence.h
/usr/include/CGAL/Polynomial/internal/Rational/Sturm_sequence_base.h
/usr/include/CGAL/Polynomial/internal/Rational/Subresultant_Sturm_sequence.h