Google, from what I found around, cites nothing, not even WHATWG.
Webkit cites MDN (which cites w3c) as a source.
Although I still worry about the case where fixing the deviance would break production apps. Potentially break them, since people won't complain until you release the breaking browser version. That's what's usually kept browsers from hewing to standards.
If there is an inconsistency between what the standards say and what the browsers have done, the browsers will more than likely trump the standards. In all practical senses the standards are descriptive, not prescriptive.