/usr/include/msgpack/preprocessor/seq/ is in libmsgpack-dev 2.1.5-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/msgpack/preprocessor/seq/cat.hpp
/usr/include/msgpack/preprocessor/seq/detail/
/usr/include/msgpack/preprocessor/seq/detail/binary_transform.hpp
/usr/include/msgpack/preprocessor/seq/detail/is_empty.hpp
/usr/include/msgpack/preprocessor/seq/detail/split.hpp
/usr/include/msgpack/preprocessor/seq/elem.hpp
/usr/include/msgpack/preprocessor/seq/enum.hpp
/usr/include/msgpack/preprocessor/seq/filter.hpp
/usr/include/msgpack/preprocessor/seq/first_n.hpp
/usr/include/msgpack/preprocessor/seq/fold_left.hpp
/usr/include/msgpack/preprocessor/seq/fold_right.hpp
/usr/include/msgpack/preprocessor/seq/for_each.hpp
/usr/include/msgpack/preprocessor/seq/for_each_i.hpp
/usr/include/msgpack/preprocessor/seq/for_each_product.hpp
/usr/include/msgpack/preprocessor/seq/insert.hpp
/usr/include/msgpack/preprocessor/seq/pop_back.hpp
/usr/include/msgpack/preprocessor/seq/pop_front.hpp
/usr/include/msgpack/preprocessor/seq/push_back.hpp
/usr/include/msgpack/preprocessor/seq/push_front.hpp
/usr/include/msgpack/preprocessor/seq/remove.hpp
/usr/include/msgpack/preprocessor/seq/replace.hpp
/usr/include/msgpack/preprocessor/seq/rest_n.hpp
/usr/include/msgpack/preprocessor/seq/reverse.hpp
/usr/include/msgpack/preprocessor/seq/seq.hpp
/usr/include/msgpack/preprocessor/seq/size.hpp
/usr/include/msgpack/preprocessor/seq/subseq.hpp
/usr/include/msgpack/preprocessor/seq/to_array.hpp
/usr/include/msgpack/preprocessor/seq/to_list.hpp
/usr/include/msgpack/preprocessor/seq/to_tuple.hpp
/usr/include/msgpack/preprocessor/seq/transform.hpp
/usr/include/msgpack/preprocessor/seq/variadic_seq_to_seq.hpp