/usr/include/boost/align/detail/ is in libboost1.62-dev 1.62.0+dfsg-4.
This file is owned by root:root, with mode 0o755.
..
/usr/include/boost/align/detail/addressof.hpp
/usr/include/boost/align/detail/align.hpp
/usr/include/boost/align/detail/align_cxx11.hpp
/usr/include/boost/align/detail/align_down.hpp
/usr/include/boost/align/detail/align_up.hpp
/usr/include/boost/align/detail/aligned_alloc.hpp
/usr/include/boost/align/detail/aligned_alloc_android.hpp
/usr/include/boost/align/detail/aligned_alloc_macos.hpp
/usr/include/boost/align/detail/aligned_alloc_msvc.hpp
/usr/include/boost/align/detail/aligned_alloc_posix.hpp
/usr/include/boost/align/detail/aligned_alloc_sunos.hpp
/usr/include/boost/align/detail/alignment_of.hpp
/usr/include/boost/align/detail/alignment_of_clang.hpp
/usr/include/boost/align/detail/alignment_of_codegear.hpp
/usr/include/boost/align/detail/alignment_of_cxx11.hpp
/usr/include/boost/align/detail/alignment_of_gcc.hpp
/usr/include/boost/align/detail/alignment_of_msvc.hpp
/usr/include/boost/align/detail/assume_aligned.hpp
/usr/include/boost/align/detail/assume_aligned_clang.hpp
/usr/include/boost/align/detail/assume_aligned_gcc.hpp
/usr/include/boost/align/detail/assume_aligned_intel.hpp
/usr/include/boost/align/detail/assume_aligned_msvc.hpp
/usr/include/boost/align/detail/element_type.hpp
/usr/include/boost/align/detail/integral_constant.hpp
/usr/include/boost/align/detail/is_aligned.hpp
/usr/include/boost/align/detail/is_alignment.hpp
/usr/include/boost/align/detail/is_alignment_constant.hpp
/usr/include/boost/align/detail/max_align.hpp
/usr/include/boost/align/detail/max_objects.hpp
/usr/include/boost/align/detail/max_size.hpp
/usr/include/boost/align/detail/min_size.hpp