Name of the new "Tab" class?

Hello,

I was wondering which class has replaced the "CloseButtonTabbedPane" class, 
which is the one that was used for the tabs of the editor?

I like the look and functionality of the replacement in 3.6beta, but I am 
having problems finding it in the source (which I only downloaded today, it 
is pretty huge to get a feel of :). It probably doesn't extend JTabbedPane, 
does it? I grepped for it, but no class seemed to extend it.

Thanks in advance.

-- 
Kind regards,
Christophe Vanfleteren