I've been hearing a few things about the Kobo .kepub format but cannot find a lot of information on it.

* What features or capabilities, if any, do you get from .kepub on a Kobo device, that you wouldn't get from a Calibre-generated .epub file?

* How do you 'convert' a liberated .epub file to the .kepub format? I don't see options for this in Calibre.