/usr/lib/python2.7/dist-packages/lxml/isoschematron/resources/rng/iso-schematron.rng is in python-lxml 2.3.2-1ubuntu0.2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.7/dist-packages/lxml/isoschematron/resources/rng/../../../../../../../share/pyshared/lxml/isoschematron/resources/rng/iso-schematron.rng