May be he means the size and type of the EPROM, the article •G40 Engine Details on start page of polog40.co.uk describes a 27c256 type EPROM. You can buy blank EPROM's at a regular electronic parts shop and are made by Texas Instruments, AMD, ST(SGS-Thompson). These can be programmed and erased (with UV light)may times.
Beware of ESD (Electro Static Discharge)!!! it can damage the EPROM and ECU electronic's while working on the ECU.
Read this article on
http://en.wikipedia.org/wiki/Electrostatic_dischargeWhat he also can mean is the get the source code of the program for G40 Digifant ECU, thats the hand written code before it is compiled to a binary file ready for the EPROM. I assume this is locked away at VW or Bosch.