It's in database table format. Your best bet may be to take 1 or 2 existing models, export them to s2k and look at the format to figure it out. Nowadays with the graphical interface, there's not much you can do with s2k that you can't do much faster using the graphical interface. Out of curiosity, is there a reason you want to work with the s2k file rather than the graphical interface?
