What is the difference between vested funds and non-vested funds in a 401(k) plan?

Vested funds are employer contributions, but non-vested funds are contributed by the employee.

Vested funds are tax-exempt until retirement, but non-vested funds are not.

Vested funds do not belong to the employee until after a set period, but non-vested funds immediately belong to the employee.

Vested funds belong to the employee even if employment ends but non-vested funds do not.