First, apple’s magsafe battery is designed with 7.62v, almost twice the voltage of alternatives on the market. that means it’s likely there are two 1460mah at about 3.7v for a total of 2920mah (creating the 7.62v apple uses on the label).
second, the capacity to deliver power over time – watt-hours (wh) is a better metric to understand what apple may deliver here. the magsafe battery’s 11.13wh compares to the iphone 12/12 pro batteries having 10.75wh.
and the iphone 12 mini has an 8.57wh battery with the iphone 12 pro max featuring a 14.13wh battery. long story short, if apple has a high efficiency (around 70-80%), after energy loss from the wireless transfer, the new magsafe battery could possibly give close to a full charge for iphone 12 mini, around 75% for the 12/pro, and around 50% for the 12 pro max.