Hello Livius
We do not have that option in the extension. I guess it's a custom field which someone defined on your site. The information on Extra Information tab, is just used to display more information about the event. It does not affect registration process. It's called Event Custom Fields, see
eventbookingdoc.joomservices.com/basic-s.../event-custom-fields
for detailed information
Regards,
Tuan
