This refers to the 4,000 people Jesus fed. Alternate translation: "the 4,000 people" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/translate-numbers]])
It may be helpful to state when they collected these. Alternate translation: "how many baskets full of broken pieces of bread did you collect after everyone finished eating" (See: [[rc://en/ta/man/translate/figs-explicit]])