WebApps and Meta.WebApps are listed, as WebApps has entered the private beta phase.
Note that the state property for those two are private_beta and linked_meta respectively, values nobody has presumably seen before (except in the docs).
Remember, a linked_meta site is implicitly in the same state as its parent site.
Also note that the site_url and name for both are temporary, assuming WebApps graduates to a full site. When/If such a graduation occurs, webapps.stackexchange.com will be moved to the aliases array (which has been documented for awhile, but has not been in use).
If you are caching objects with respect to their site, be sure to check aliases in addition to site_url when doing a lookup.
icon_urlis 404ing -- is this going to be added during the beta? I wasnt sure if "pick the icon" is part of the Area51 stuff or if it was decided when the site launches.