Hi Tom,
As you said it is an Incubator Group. It is not on the standards track. W3C is a platform for working. Incubator Activity offers a space for people with similar needs to work on a topic that matters to them. There is almost no human resources allocated by W3C Team on these projects. There are managed by the companies involved into it. Incubator Activity is a focused on studying and publishing very quickly: one year to achive the work. There is more information on
http://www.w3.org/2005/Incubator...ator/
about.html
The charter of the CWL Incubator group gives a bit more details.
http://www.w3.org/2005/Incubator.../cwl-ei/
charter
As you can see in the charter, it is a group of Japanese members organizations and companies which are studying this topic.
If you want to know a bit more of UNL which is not new at all :) It is part of a Programme started in 1996 of the Institute of Advanced Studies of United Nations University
http://www.undl.org/
Another place where you can find documents which are not part of the Standards track is the Member Submission page.
http://www.w3.org/Submission/