The main responsibility of the Development Working Group is taking care of the development of the Joomla! application framework and the Joomla! Content Management System (CMS). Besides the development of the Joomla! codebase the development working group defines the Joomla! roadmap strategy, creating (architectural) designs for major and minor versions and of course take care of bug and security fixes in maintenance versions.
The development working group holds two teams: the Development Team and the so called Bug Squad. Both teams have a separate responsibility but together they form the development force for the Joomla! project.