/usr/lib/python2.7/dist-packages/zope/testrunner/tests/testrunner-ex/sample3/post_mortem_failure.txt is in python-zope.testrunner 4.4.2-0ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | >>> x = 1
>>> x
2
|