/usr/lib/python2.6/dist-packages/trytond/modules/stock_location_sequence/stock.py is in tryton-modules-stock-location-sequence 2.2.0-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.6/dist-packages/trytond/modules/stock_location_sequence/../../../../../../share/pyshared/trytond/modules/stock_location_sequence/stock.py