/usr/include/boost/ratio/ is in libboost1.62-dev 1.62.0+dfsg-5.
This file is owned by root:root, with mode 0o755.
..
/usr/include/boost/ratio/config.hpp
/usr/include/boost/ratio/detail/
/usr/include/boost/ratio/detail/mpl/
/usr/include/boost/ratio/detail/mpl/abs.hpp
/usr/include/boost/ratio/detail/mpl/gcd.hpp
/usr/include/boost/ratio/detail/mpl/lcm.hpp
/usr/include/boost/ratio/detail/mpl/sign.hpp
/usr/include/boost/ratio/detail/overflow_helpers.hpp
/usr/include/boost/ratio/detail/ratio_io.hpp
/usr/include/boost/ratio/include.hpp
/usr/include/boost/ratio/mpl/
/usr/include/boost/ratio/mpl/abs.hpp
/usr/include/boost/ratio/mpl/arithmetic.hpp
/usr/include/boost/ratio/mpl/comparison.hpp
/usr/include/boost/ratio/mpl/divides.hpp
/usr/include/boost/ratio/mpl/equal_to.hpp
/usr/include/boost/ratio/mpl/gcd.hpp
/usr/include/boost/ratio/mpl/greater.hpp
/usr/include/boost/ratio/mpl/greater_equal.hpp
/usr/include/boost/ratio/mpl/lcm.hpp
/usr/include/boost/ratio/mpl/less.hpp
/usr/include/boost/ratio/mpl/less_equal.hpp
/usr/include/boost/ratio/mpl/minus.hpp
/usr/include/boost/ratio/mpl/negate.hpp
/usr/include/boost/ratio/mpl/not_equal_to.hpp
/usr/include/boost/ratio/mpl/numeric_cast.hpp
/usr/include/boost/ratio/mpl/plus.hpp
/usr/include/boost/ratio/mpl/rational_c_tag.hpp
/usr/include/boost/ratio/mpl/rational_constant.hpp
/usr/include/boost/ratio/mpl/sign.hpp
/usr/include/boost/ratio/mpl/times.hpp
/usr/include/boost/ratio/ratio.hpp
/usr/include/boost/ratio/ratio_fwd.hpp
/usr/include/boost/ratio/ratio_io.hpp