Sure, the features may be the same, but the implementation could very well be proprietary and someone else's IP. That's the case ISTR being laid out in some detail with names and dates, regarding code that Apple bought to include in various releases, but on limited license. Later, a different license applied.

Of course, I can't be arsed chasing down the reference, so we'll all just have to assume that my glorious and infallible memory is 100% correct, mkay?

Still, I assume that something very like what you describe above happened too.

I have another theory: that Apple's forgotten this page even exists, and we should all just keep vewwy vewwy quiet about it.