source (.drv) files for cups ppd files?

[Gary Aitken]

I'm trying to figure out how to improve the ppd file for the epson 3880
printer, and in order to do that I need the source (.drv) files used to
create the ppd file.  I thought it should have been in one of the cups
ports, but after expanding them I don't see it.  All that is there is
the ppd files for the individual printers, each separately gzipped up.

Am I missing something?  

Thanks for any clues,

Gary