/usr/lib/python3/dist-packages/celery/backends/ is in python3-celery 3.1.20-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python3/dist-packages/celery/backends/__init__.py
/usr/lib/python3/dist-packages/celery/backends/amqp.py
/usr/lib/python3/dist-packages/celery/backends/base.py
/usr/lib/python3/dist-packages/celery/backends/cache.py
/usr/lib/python3/dist-packages/celery/backends/cassandra.py
/usr/lib/python3/dist-packages/celery/backends/couchbase.py
/usr/lib/python3/dist-packages/celery/backends/database/
/usr/lib/python3/dist-packages/celery/backends/database/__init__.py
/usr/lib/python3/dist-packages/celery/backends/database/models.py
/usr/lib/python3/dist-packages/celery/backends/database/session.py
/usr/lib/python3/dist-packages/celery/backends/mongodb.py
/usr/lib/python3/dist-packages/celery/backends/redis.py
/usr/lib/python3/dist-packages/celery/backends/rpc.py