CSS3 :unchecked pseudo-class

I know there is an official CSS3 :checked pseudo-class, but is there an :unchecked pseudo-class, and do they have the same browser support?

Sitepoint's reference doesn't mention one, however this whatwg spec (whatever that is) does.

I know the same result can be achieved when the :checked and :not() pseudo-classes are combined, but i'm still curious:

input[type="checkbox"]:not(:checked) {
    /* styles */
}

Edit:

The w3c recommends the same technique

An unchecked checkbox can be selected by using the negation pseudo-class:

:not(:checked)