/usr/ is in postgresql-plpython3-9.5 9.5.2-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/
/usr/lib/postgresql/
/usr/lib/postgresql/9.5/
/usr/lib/postgresql/9.5/lib/
/usr/lib/postgresql/9.5/lib/hstore_plpython3.so
/usr/lib/postgresql/9.5/lib/plpython3.so
/usr/share/
/usr/share/postgresql/
/usr/share/postgresql/9.5/
/usr/share/postgresql/9.5/extension/
/usr/share/postgresql/9.5/extension/plpython3u--1.0.sql
/usr/share/postgresql/9.5/extension/hstore_plpython3u.control
/usr/share/postgresql/9.5/extension/plpython3u--unpackaged--1.0.sql
/usr/share/postgresql/9.5/extension/plpython3u.control
/usr/share/postgresql/9.5/extension/hstore_plpython3u--1.0.sql
/usr/share/doc/
/usr/share/doc/postgresql-plpython3-9.5/
/usr/share/doc/postgresql-plpython3-9.5/copyright
/usr/share/doc/postgresql-plpython3-9.5/changelog.Debian.gz