A request for comments has been opened on whether a c: interwiki prefix should be added for Wikimedia Commons. The RfC follows a 2011 RfC on the same topic which, while positive, did not see wide participation.
User groups (various types of groups, e.g., sysop, bureaucrat, etc.)
Core issues and collaboration
Helping contribute and collaborate (i.e., what makes it easy, what makes it hard, how to do it well, why you have to, what conflicts typically arise, fixing them). Discussing and formulating project-wide (i.e. not language-specific) policies.