Apple has been slowly open sourcing its stuff ever since swift came out. Research kit was open sourced not to long ago. What stuck out the most with that reveal is the lack of swift. You’d think that apple would have all swift by now.

It makes me wonder if swift is being used at all by Apple internally….

I found my answer https://daringfireball.net/thetalkshow/139/federighi-gruber-transcript

The teams in Apple have varying interest in swift ranging from love it to apathetic. Teams that love it go and try to add it to their project. Like the team working on the OS X Dock. However there are some teams that are not able to use swift. Some teams need to support 32 bit architecture and are not able to support that; therefore they stick with objective-c

Other Apple teams see swift as an unstable language undergoing a growth spurt. They might love it but to fit it in their project may be the wrong timing. Luckily some teams are using swift for unit testing.

So my prediction in next swift, swift 3, is there will be more Apple swift projects.

Maybe in wwdc they will tell us which apps/components use swift and we can better appreciate the masterpiece.