Why does the System.Type overload equality operator?

Question

Docs don't answer. Sources also:

    [System.Security.SecuritySafeCritical]
    [Pure]
    [ResourceExposure(ResourceScope.None)]
    [MethodImplAttribute(MethodImplOptions.InternalCall)]
    public static extern bool operator ==(Type left, Type right);

So, I'm curious why System.Type overloads operator ==? Could there be more than 1 instance of Type class representing some particular type? Or what else could be in the overloaded operator definition?