The words "how" and "has" are understood. Alternate translation: "how the proud fury has ended" or "his pride and fury have ended" (See: [[rc://en/ta/man/translate/figs-ellipsis]])
The "proud fury" refers to the king of Babylon being proud and treating other nations cruelly. Alternate translation: "his cruelty has ended" or "he can no longer oppress people" (See: [[rc://en/ta/man/translate/figs-metonymy]])