bigint ↔ Numeric Primitive Value to rep integer with arbitrary precision to store numbers > Number.MAX_SAFE_INTEGER

References

1. Primitive Value ↔ undefined, null, number, bigint, boolean, string, symbol

2. BigInt ↔ Autoboxing Wrapper for bigint Primitive

3. UNNBBSS ↔ undefined, null, number, bigint, boolean, string, symbol