Nothing. There's been no real news about it at all. All we know is it's going to be a part of the Dawntrail era and that it will be a Limited Job.

Apart from that, nothing is known and been released. Personally I doubt it will be available at DT's release, but will be added in a patch later on, probably the first numbered main content patch around the end of the year, like how BLU was added much later on in SB's life.