Representation of a
This is a product type introduced by defprod.
This is the file format used by the vl-server. It contains a pre-parsed Verilog design, all the source code used to create it, and other information.
We write out vl-zipfile structures in a special format so that we can
read the VL syntax version, creation date, and design name without having to
read the contents of the design. This allows us to (in the VL server) quickly