"Diversity tickets available" means that there are discounted/free tickets available for people who couldn't otherwise afford them, and are from backgrounds tha

"Diversity tickets available" means that there are discounted/free tickets available for people who couldn't otherwise afford them, and are from backgrounds that aren't well represented. At least for events I've been involved in that's more nuanced than "women etc", and could just as easily mean an open source contributor who doesn't have a corporate sponsor to buy a ticket for them, but does have an interest in the subject.