The official posting notes that support at this time is highly experimental and may be discontinued at any time on the whims of the developers. UI support is also very primitive, which could lead to issues with the game experience beyond just looking at stuff. Despite that fact, the support is available for testing now on the public test server and is expected to go live this Wednesday, giving players a chance to play around with the support and see how they like it. Assuming they have Rifts, of course.
[Thanks to Rick from Santa Cruz for the tip!]