TMK, there is no public passcode for the memory edit screen.
As for what is there, nearly everything that is kept when power is removed, and is not directly security related.
Mostly it would be channel maps, TZ settings, and user preferences. I would think the guide flag and geographic exclustion code is in the security chip.
For the "hit" carousel, IME it used to occur every day during late evening, although my 301 took a couple days to get its hit last time I put it in service from storage. A packagae change might trigger a hit.