/etc/gforge/plugins/scmbzr/serve-branches.conf is in fusionforge-plugin-scmbzr 5.3.2+20141104-3+deb8u3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | served_branches=/var/lib/gforge/plugins/scmbzr/public-repositories
prefix=/scm/loggerhead
port=8081
|