He may regret this, but he has taught this skill to N, the other boy cat in the household. I say he may regret it because N uses this primarily to break into my room and steal P's food while he is eating.
When possible I try to only feed Pretzel when I am there. But sometimes laundry needs to go in, or I'm doing three other things, or I have to run out the door and it's the last minute. Whatever. Well, N is taking advantage of those times.
"No problem," I thought to myself when I realized he had learned to open the door. "I'll just use the privacy screen." it's wooden, six feet tall and thirty or forty pounds. I set it up to cross the hall, even put a laundry basket in front of it for extra security. But it was no match for the might N. He nosed the basket out of the way then used his paw to open the screen. Amazing.
So, I now have to supervise Pretzel feedings personally.