/usr/lib/python2.7/dist-packages/mock-1.0.1.egg-info/top_level.txt is in python-mock 1.0.1-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.7/dist-packages/mock-1.0.1.egg-info/../../../../share/pyshared/mock-1.0.1.egg-info/top_level.txt