osTicket is striving to develop the world's most popular open source ticketing system more openly. Starting with osTicket 1.7, the mainline development has been available on GitHub. If you are maintaining or creating a customized version of osTicket, using git and following the mainline development's GitHub repo can make you far more successful.
Follow the Source
GitHub allows you to fork the mainline repository and make custom changes to the software, while tracking the mainline development and allowing you to merge upstream changes into your custom code.