/usr/share/ltsp/plugins/ltsp-build-client/Debian/099-progress-log is in ltsp-server 5.4.2-6+deb7u1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | # FIXME: this plugin is a hack to make some sort of progress on the major
# points of the install, used by ltsp-client-builder udeb in debian-installer.
echo $(date) MODE:$MODE >> /var/log/ltsp-build-client.progress.log || true
|