> ...
> %!PS-Adobe-3.1 EPSF-3.0
>
> does anyone know where the 3.1 came from
> ...
The number after 'PS-Adobe-' is the DSC version (note that EPS comments are
basically those in the DSC, with few specifics). The one after EPSF- is the
version of the EPS specification.
> ... and what the differences between 3.1 and 3.0 would be?
I found no DSC reference newer than 3.0. If someone knows where to get one,
I'm all ears (eh, eyes, 'cause it's in writing...). I can only speculate it
could be the result of merging part or all of TechNote #5644 "PostScript
Language Document Comment Extensions for Page Layout" (see
http://partners.adobe.com/public/developer/ps/index_specs.html), and maybe
something more too, into DSC 3.0.