Elastic support diagnostics, Scrub.bat -c parameter

Contains an example

/scrub.sh -i '/Users/adminuser/diagnostic output/diagnostics-20180621-161231.zip' -o /home/adminuser/sanitized-diags -c /home/adminuser/sanitized-diags/scrub.yml

What is the -c parameter?

scrub.bat -? gives options but not -c

There was a previous command line option to specify the scrub.yml config file, but that was removed.