The term "pitch framing" is a misnomer that euphemizes its true nature. The correct term is "faking out the home plate umpire". The fact that there are metrics for it and that it's a topic of discussion on this web site strongly reflects the need for the implementation of a good automated pitch calling system ASAP.
Incorrect. Most catchers I've spoken to hate the term "pitch framing". The correct term is "receiving the ball the right way".
That doesn't just mean "stealing strikes". It also means keeping pitches in the zone from being called balls. This was as significant problem for the Twins from 2014-2016: They'd lose more pitches in the strike zone than any other teams.
The Astros were one of the best at the "framing" statistic in that time. Here's what Castro said about what the Astros' focused on:
“Keeping strikes in the strike zone,” he explained. “Not doing anything to the pitch to take away from its quality. If it is on the corner and it is breaking one direction, you are trying to counteract the break so it doesn’t, by the time you catch the ball, pull your arm out of the zone.”
It's not about yanking a glove back across the plate -- it's about receiving the ball in a manner that maximizes the pitcher's intent.