Hi Dave,
Thanks for reaching out with your question, and for your patience while we worked to get back to you on this.
Unfortunately, there's not currently an internal filter that allows for searching for attendees by barcode number. Do you mind going into a little more detail about your use-case here? While we don't have the specific functionality you're looking for, we may have a feasible workaround, depending on what you're trying to do specifically.
That being said, your discovery regarding the bardcode # and how it breaks down into the component pieces of Order ID, Attendee ID, and Ticket # on the order are exactly correct. So unfortunately, for the time being, the workaround of returning all attendees, and then searching for a barcode match would be the option that we suggest as well.
I look forward to hearing back from you.
Best,
-Jacob
Eventbrite Developer Support