New b3ds format?

Has Mark released a specification for the new .b3ds format? I'm in the process of writing a modeling/animation app, and would like to include both .b3d and .b3ds formats, but I can only find documentation for the .b3d file format. I already checked in the spec/utils section of the website, but haven't seen the new format in it.

There is no .b3ds format. The .b3ds mentioned on the front page was merely referring to the .b3d format in the plural sense.