With KHTML they became the <i>de facto</i> upstream very quickly, though it took a few years for the KDE people to play along, become downstream, and make it <i>de jure</i>.<p>Apple has employed a bunch of the FreeBSD developers, but there's really not that much relevant code there, much less contributable code. The non-mac-specific patches to the userland utilities does make it upstream.<p>You are correct in that most of the FOSS projects that Apple picks up were playing for relative tiddlywinks before they came along with piles of money (excepting GCC and maybe CUPS). They're one of the only companies that has done this kind of thing with any success.