/usr/lib/python3/dist-packages/twisted/plugins/ is in python3-twisted 16.6.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python3/dist-packages/twisted/plugins/__init__.py
/usr/lib/python3/dist-packages/twisted/plugins/cred_anonymous.py
/usr/lib/python3/dist-packages/twisted/plugins/cred_file.py
/usr/lib/python3/dist-packages/twisted/plugins/cred_memory.py
/usr/lib/python3/dist-packages/twisted/plugins/cred_sshkeys.py
/usr/lib/python3/dist-packages/twisted/plugins/cred_unix.py
/usr/lib/python3/dist-packages/twisted/plugins/twisted_core.py
/usr/lib/python3/dist-packages/twisted/plugins/twisted_reactors.py
/usr/lib/python3/dist-packages/twisted/plugins/twisted_trial.py
/usr/lib/python3/dist-packages/twisted/plugins/twisted_web.py