One of the powers of O2 is that is allows the automation of repetitive tasks via scripts
This usually means automating some Web Vulnerability Browser workflow or an specific Static Analysis of source code.
In this case what we have here is an non-professional programmer or security consultant, Sarah Baso from OWASP, writing/customizing an O2 script to batch create the attendee and speaker participation certificates of the OWASP AppSec Brazil.
I think Sarah based her code on this 2010 O2 Script: Creating PDFs with OWASP AppSec Brazil Certificates.
Here is what the 2011 version (of a PDF created from a DB list of users) looks like: