/usr/lib/python2.7/dist-packages/acct_mgr/templates/user_changes_email.txt is in trac-accountmanager 0.4.3-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.7/dist-packages/acct_mgr/templates/../../../../../share/pyshared/acct_mgr/templates/user_changes_email.txt