The bowl cache is garbage collected with a stop the world collection step wherein the bowl is upended and the contents returned, the bottom cleaned, and a few select items pre-seeded in the fresh cache.
Overflow actually spills off the top. It's MRU!
Yeah, but it spills off onto the table top, which is effectively register space.
If you put the s**bowl on top of an old cash register, it overflows into an actual register.