Schneider 300mm f5.6 variable focus mystery lens

I recently purchased a Schneider 300mm f5.6 - f11 lens on eBay. The lens appears to be a copy or enlarging lens, however it either has a variable focal length or most probably a focus function. The sellor reports that only about 100 were made, and they were originally very expensive being made for a US military contract. The lens is not marked Schneider, the only marking is "made in Germany" with the following series of numbers "12595715". It is reported that it was designed for a copy camera with extremely high resolution. It weighs approximately 6 lbs with a 98mm filter size and a 3 1/2 inch mounting flange. Schneider is reportedly not willing to provide info on them. I am planning to use it as an enlarging lens on an 8x10 Saltzman. I have already mounted it and it is excellent. I would welcome any additional information anyone might have on this exceptional piece of glass. The ebay photos may be seen at

http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=119754190