To bring it back on topic, the prenup says 2 things:
1. Each spouse agrees to appear before a panel of Jewish law judges (dayanim) arranged by the Beth Din of America, if the other spouse demands it, and to abide by the decision of the Beth Din with respect to the get.
2. If the couple separates, the Jewish law obligation of the husband to support his wife is formalized, so that he is obligated to pay $150 per day (indexed to inflation), from the date he receives notice from her of her intention to collect that sum, until the date a Jewish divorce is obtained. This support obligation ends if the wife fails to appear at the Beth Din of America or to abide by a decision of the Beth Din of America.
The Nachalas Shiva was a sefer of shtaros published in 1664 by Shmuel Ben David Moshe Halevi, and one of the forms he included was a tenaim almist exactly similar to the provisions in the prenup, and he says that this dated back to the Takanos Shum, the authoritative communal enactments adopted in the early Middle Ages by the leaders of the German communities of Speyer, Worms and Mayence.