Some ideas we work on may use software that is licensed under Eclipse-incompatible Licenses like GPL. Other ideas are implemented by externals or students and may have an unclear outcome. These repositories can not be hosted by the Eclipse Foundation for various reasons as they may contain code not conforming to the Eclipse license requirements etc.
Since these projects cannot be hosted at Eclipse we use http://eclipselabs.org as hosting platform - and as soon as those experiments create promising results we transfer the knowledge obtained from these projects back to Eclipse and ensure IP compliance.
Please visit our eclipselabs page for a list of currently hosted lab projects.