CampTix is the plugin used on WordCamp.org sites to sell tickets to WordCamp events and manage attendee data. Since 2012, when it was first built, it has also been distributed as a standalone plugin in the WordPress.org plugin directory.
WordCamp.org has always run the same CampTix code as that found in the plugin directory. A few months ago, however, it was necessary to add some functionality from other parts of the WordCamp codebase into CampTix. Copying that functionality into the standalone plugin would have created confusing duplication on WordCamp sites, and added a lot of complexity to the update. Instead,