/usr/include/boost/proto/functional/ is in libboost1.62-dev 1.62.0+dfsg-5.
This file is owned by root:root, with mode 0o755.
..
/usr/include/boost/proto/functional/fusion/
/usr/include/boost/proto/functional/fusion.hpp
/usr/include/boost/proto/functional/fusion/at.hpp
/usr/include/boost/proto/functional/fusion/pop_back.hpp
/usr/include/boost/proto/functional/fusion/pop_front.hpp
/usr/include/boost/proto/functional/fusion/push_back.hpp
/usr/include/boost/proto/functional/fusion/push_front.hpp
/usr/include/boost/proto/functional/fusion/reverse.hpp
/usr/include/boost/proto/functional/range/
/usr/include/boost/proto/functional/range.hpp
/usr/include/boost/proto/functional/range/begin.hpp
/usr/include/boost/proto/functional/range/empty.hpp
/usr/include/boost/proto/functional/range/end.hpp
/usr/include/boost/proto/functional/range/rbegin.hpp
/usr/include/boost/proto/functional/range/rend.hpp
/usr/include/boost/proto/functional/range/size.hpp
/usr/include/boost/proto/functional/std/
/usr/include/boost/proto/functional/std.hpp
/usr/include/boost/proto/functional/std/iterator.hpp
/usr/include/boost/proto/functional/std/utility.hpp