Six post-definition dict-set! calls add .length=1 and .name="<Ctor>" to the global constructor dicts. Per spec Number/String/Array/Boolean/ Object all have length 1 (they take one arg). Unit 521/522, slice 148/148 unchanged. Number scoreboard: 52/100 → 53/100 (+1, S15.7.3_A8: Number.length==1).