How does Populate Header Descriptive Details work?

I'm having some issues with budget revisions, and it seems to go back a rule that is attached to a form that runs on a save. However, this rule ( OEP_FS - Rule - Populate Header Descriptive Details) is apparently a rule that cannot be customized or viewed. I checked with Support, and they told me as much, but they also said they were unable to find the code for the script for this rule. It would be extremely helpful to me to debug a variety of issues we're having with these revisions if I could see the