/usr/lib/python2.7/dist-packages/keystonemiddleware-4.21.0.egg-info/requires.txt is in python-keystonemiddleware 4.21.0-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | [audit_notifications]
oslo.messaging>=5.29.0
|