/usr/share/octave/4.2.2/m/help/ is in octave-common 4.2.2-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/octave/4.2.2/m/help/__gripe_missing_component__.m
/usr/share/octave/4.2.2/m/help/__makeinfo__.m
/usr/share/octave/4.2.2/m/help/__unimplemented__.m
/usr/share/octave/4.2.2/m/help/ans.m
/usr/share/octave/4.2.2/m/help/doc.m
/usr/share/octave/4.2.2/m/help/doc_cache_create.m
/usr/share/octave/4.2.2/m/help/error_ids.m
/usr/share/octave/4.2.2/m/help/get_first_help_sentence.m
/usr/share/octave/4.2.2/m/help/help.m
/usr/share/octave/4.2.2/m/help/lookfor.m
/usr/share/octave/4.2.2/m/help/print_usage.m
/usr/share/octave/4.2.2/m/help/private/
/usr/share/octave/4.2.2/m/help/private/__additional_help_message__.m
/usr/share/octave/4.2.2/m/help/private/__strip_html_tags__.m
/usr/share/octave/4.2.2/m/help/type.m
/usr/share/octave/4.2.2/m/help/warning_ids.m
/usr/share/octave/4.2.2/m/help/which.m