/usr/share/postgresql/9.5/tsearch_data/ is in postgresql-9.5 9.5.14-0ubuntu0.16.04.
This file is owned by root:root, with mode 0o755.
..
/usr/share/postgresql/9.5/tsearch_data/danish.stop
/usr/share/postgresql/9.5/tsearch_data/dutch.stop
/usr/share/postgresql/9.5/tsearch_data/english.stop
/usr/share/postgresql/9.5/tsearch_data/finnish.stop
/usr/share/postgresql/9.5/tsearch_data/french.stop
/usr/share/postgresql/9.5/tsearch_data/german.stop
/usr/share/postgresql/9.5/tsearch_data/hungarian.stop
/usr/share/postgresql/9.5/tsearch_data/hunspell_sample.affix
/usr/share/postgresql/9.5/tsearch_data/ispell_sample.affix
/usr/share/postgresql/9.5/tsearch_data/ispell_sample.dict
/usr/share/postgresql/9.5/tsearch_data/italian.stop
/usr/share/postgresql/9.5/tsearch_data/norwegian.stop
/usr/share/postgresql/9.5/tsearch_data/portuguese.stop
/usr/share/postgresql/9.5/tsearch_data/russian.stop
/usr/share/postgresql/9.5/tsearch_data/spanish.stop
/usr/share/postgresql/9.5/tsearch_data/swedish.stop
/usr/share/postgresql/9.5/tsearch_data/synonym_sample.syn
/usr/share/postgresql/9.5/tsearch_data/thesaurus_sample.ths
/usr/share/postgresql/9.5/tsearch_data/turkish.stop
/usr/share/postgresql/9.5/tsearch_data/unaccent.rules
/usr/share/postgresql/9.5/tsearch_data/xsyn_sample.rules