The Importance of Ad Hoc Saves in Popper's Epistemology

Deutsch spends a lot of time on the importance of not having bad explanations. But he misses the fact that every single theory, including really good theories like quantum physics, can be easily tweaked if you're willing to fit any possible outcome. Now, Deutsch never talks about ad hoc saves. I just think it wasn't something that came up in his books. It's actually important to understanding the concept of a bad explanation. And Deutsch never brings this out. So let me explain Popper's idea of ad hoc saves and why they're important to his epistemology.