After much searching on the Internet for this term, the only translation I can come up with is "fabricación según especificaciones de terceros", explanation which I have found on a Dutch website (in Dutch). I can tell you as well that all the websites where I found, the term referred to manufacturing of chemical products.
In your case, probably, one company is going to manufacture a (set of) products according to the "recipe" or specifications of the other. At the link below you can find a short explanation of its meaning.
Hope it helps!!
Un saludo.