Mac OS X
The instance for Mac computers does not run natively on OS X. It requires an open-source application called XQuartz, that implements the X.Org X Window System.
This system is the X11.app that Apple no longer includes with the latest versions of its operating systems. It was discontinued after 10.7.
At this time, team members working on the Mac instance are still switching it to handle Gtk and Glib libraries for OS X. There is an unstable version that runs on OS X.
