/usr/include/pegtl/internal/ is in pegtl-dev 1.3.1-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/pegtl/internal/action.hh
/usr/include/pegtl/internal/any.hh
/usr/include/pegtl/internal/at.hh
/usr/include/pegtl/internal/bump_util.hh
/usr/include/pegtl/internal/bytes.hh
/usr/include/pegtl/internal/control.hh
/usr/include/pegtl/internal/demangle.hh
/usr/include/pegtl/internal/demangle_cxxabi.hh
/usr/include/pegtl/internal/demangle_nop.hh
/usr/include/pegtl/internal/disable.hh
/usr/include/pegtl/internal/enable.hh
/usr/include/pegtl/internal/eof.hh
/usr/include/pegtl/internal/eol.hh
/usr/include/pegtl/internal/eolf.hh
/usr/include/pegtl/internal/file_mapper.hh
/usr/include/pegtl/internal/file_opener.hh
/usr/include/pegtl/internal/file_reader.hh
/usr/include/pegtl/internal/if_must.hh
/usr/include/pegtl/internal/if_must_else.hh
/usr/include/pegtl/internal/if_then_else.hh
/usr/include/pegtl/internal/input_data.hh
/usr/include/pegtl/internal/input_mark.hh
/usr/include/pegtl/internal/input_pair.hh
/usr/include/pegtl/internal/istring.hh
/usr/include/pegtl/internal/list.hh
/usr/include/pegtl/internal/list_must.hh
/usr/include/pegtl/internal/list_tail.hh
/usr/include/pegtl/internal/list_tail_pad.hh
/usr/include/pegtl/internal/must.hh
/usr/include/pegtl/internal/not_at.hh
/usr/include/pegtl/internal/one.hh
/usr/include/pegtl/internal/opt.hh
/usr/include/pegtl/internal/pad.hh
/usr/include/pegtl/internal/pad_opt.hh
/usr/include/pegtl/internal/peek_char.hh
/usr/include/pegtl/internal/peek_utf16.hh
/usr/include/pegtl/internal/peek_utf32.hh
/usr/include/pegtl/internal/peek_utf8.hh
/usr/include/pegtl/internal/pegtl_string.hh
/usr/include/pegtl/internal/plus.hh
/usr/include/pegtl/internal/raise.hh
/usr/include/pegtl/internal/range.hh
/usr/include/pegtl/internal/ranges.hh
/usr/include/pegtl/internal/rep.hh
/usr/include/pegtl/internal/rep_min.hh
/usr/include/pegtl/internal/rep_min_max.hh
/usr/include/pegtl/internal/rep_opt.hh
/usr/include/pegtl/internal/result_on_found.hh
/usr/include/pegtl/internal/rule_conjunction.hh
/usr/include/pegtl/internal/rule_match_one.hh
/usr/include/pegtl/internal/rule_match_three.hh
/usr/include/pegtl/internal/rule_match_two.hh
/usr/include/pegtl/internal/rules.hh
/usr/include/pegtl/internal/seq.hh
/usr/include/pegtl/internal/skip_control.hh
/usr/include/pegtl/internal/sor.hh
/usr/include/pegtl/internal/star.hh
/usr/include/pegtl/internal/star_must.hh
/usr/include/pegtl/internal/state.hh
/usr/include/pegtl/internal/string.hh
/usr/include/pegtl/internal/trivial.hh
/usr/include/pegtl/internal/try_catch_type.hh
/usr/include/pegtl/internal/until.hh