Explain why jquery.className disappears?

Explain why jquery.className disappears?

I've been loooking at the core because I'm making a couple of extensions that behave like addClass and removeClass.  There, I've come across jquery.className, which is defined and used in the core - but it is not a property of jQuery when I ask for it after page load.

I can't find where it gets removed!  Please could someone explain where, when and why is it removed?

Obviously I can call addClass and removeClass from within my extensions (I'd prefer not to have the overhead of the extra .each() calls, though) - but really I just want a better understanding of what's going on here.

Cheers!
Stephen.