/usr/lib/python2.6/dist-packages/zope.cachedescriptors-3.5.1.egg-info/namespace_packages.txt is in python-zope.cachedescriptors 3.5.1-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.6/dist-packages/zope.cachedescriptors-3.5.1.egg-info/../../../../share/pyshared/zope.cachedescriptors-3.5.1.egg-info/namespace_packages.txt