Is expiation (kaffarah) obligatory for one who intentionally broke their fast in order to commit zina, and is the expiation for breaking the fast or for committing zina?

Adultery is one of the gravest major sins, and its حرمة (sacred inviolability) and sinfulness increase in Ramadan. So, whoever commits adultery during the daytime in Ramadan must offer sincere repentance, and the hadd (prescribed punishment) for adultery must be applied to him if his case is brought before the ruler with evidence or confession. In addition, a severe expiation (kaffara mughallazhah) is obligatory upon him, which is: freeing a slave; if he cannot find one, then fasting for two consecutive months; if he is unable to do that, then feeding sixty poor people. This expiation is not waived by repentance.