Well, we had to come up with some sort of answer since the canon didn't give us one.

"That actually sounds pretty good. Maybe I should order that."

Oh yes, she didn't explain that about this place.

"In addition to connecting to many different worlds, this place can get food from all of those worlds. It's why I'm able to get grog loaf, Every Flavour Beans, fried paradoxes, any food or drink that's ever existed anywhere. This place can also provide clothes, periodicals, keys to rooms, and pretty much anything that isn't alive or a weapon."