Pssssst. He didn’t. Legally. Not even remotely close. Not even in the same galactic cluster as a canonically valid papal resignation.
Here is point 1 of 6. Do click over and read the whole thing at Tim’s place in St. Louis.
1. One must always remember that only a pope can abolish a motu proprio issued by the pope. This “duh” principle must always be remembered in our corrupt times. Let’s just spitball, and “speculate”, that Pope Benedict is still the pope. Who cares what a heretical prelate from Argentina says about Summorum Pontificum? His authority to do anything about it is about the same as his authority in my homeowners association: zero. But, for the sake of completeness, let us assume, arguendo for the rest of this post that Bergoglio is definitively and actually the pope….