2.1.8 [ECMA-262/5] Section 184.108.40.206, Object.prototype.valueOf ()
The specification states:
2. If O is the result of calling the Object constructor with a host object (220.127.116.11), then a. Return either O or another value such as the host object originally passed to the constructor. The specific result that is returned is implementation-defined.
IE9 Mode, IE10 Mode, and IE11 Mode (All Versions)
When O is the result of calling the Object constructor with a host object, the this value is returned.