/usr/lib/python2.7/dist-packages/trytond/modules/account_invoice/locale/de_DE.po is in tryton-modules-account-invoice 2.2.1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.7/dist-packages/trytond/modules/account_invoice/locale/../../../../../../../share/pyshared/trytond/modules/account_invoice/locale/de_DE.po