I hadn’t seen any mention of this yet when I started my Leopard upgrade, but
[Apple][apple] has added the [source code][leopard] for the open-source parts
of [Leopard][macosx] on the [Darwin source][darwin] site. And yes, Virginia,
that includes [the kernel][xnu].
[apple]: http://www.apple.com/
[leopard]: http://www.opensource.apple.com/darwinsource/10.5/
[macosx]: http://www.apple.com/macosx/
[darwin]: http://www.opensource.apple.com/darwinsource/
[xnu]: http://www.opensource.apple.com/darwinsource/10.5/xnu-1228/