I am developing an application to parse PI Base Subsystem audit files and e-mail the results daily. So far, I've processed point edits and classic point additions and deletions. Today, I started on totalizers. To that effect, I created a totalizer tag, forced a backup and then ran pidiag -xa to generate an XML output. When reading through the attributes, I found ptclassrev. What exactly is it? I searched documentation that shows it exists, but what is its purpose and what would an effective description be?