That's what this says http://www.seedsofitaly.com/product/683
"Jam Pumpkins are grown extensively in Italy and are used soley for making jam, a job for which normal pumpkin varieties are unsuitable. Sow from Feb-Jun and harvest from the end of the summer and into the autumn. Mid/Early. Vigorous plant of good production forming round fruits squashed at their poles. The orange skin is slightly blistered and the flesh is very sweet. This variety is commonly used in Italy for the preparation of Pumpkin jam/preserve."
I have not tried making pumpkin jam but there are recipes on Google. The recipes require the addition of acid and pectin, but I think that it could be made with any type of pumpkin.
Have made pumpkin jam. First time with Crown prince, and it was very grainy, so that type doesn't seem suitable. Second time with one I can't recall name of exactly but it was something or other Delikata, which had a smoother flesh and was better. I cubed it small, and cooked it with some wild apple flesh, any would do I think as long as the apple pulps up nicely. It was ok, texture was fine, but taste was nothing to write home about. Bit sweet for me. I guess they don't have the choice of as many nice sharp berries in Italy as we do here.