Its up to the browser to provide it. Safari's is Safari (<version-number>). This goes all the way back to 1.1 at least (current is 2.04 I think).
This is annoying because it fragment's all the Safari versions across our metrics report. It does not say khtml I don't think - did it ever? Not sure.
Maybe I'm biased, but I'd behave the same way in their shoes. KHhtml just provides the parser and the DOM I think - basically it does the same thing I did for Scrutinizer. The converting DOM to pixels is done in a platform dependent way through Apple's Qt compatibility library that in turn calls Quartz. Many fixes end up in this layer and don't help the K people. Oh well. Do they have to back port all those changes to K's rendering engine?
I don't see why they should. Its a completely different beast.
I don't think I'm blinded by the RDF - but I do identify with the people involved in this instance.