Fantastic news that Swift is now open-source, though it came about 4 hours too late for my GotoBerlin presentation on Swift 2 Under the Hood (on SpeakerDeck at https://speakerdeck.com/alblue/swift-2-under-the-hood-gotobe... if you're interested)
I've also open-sourced the SIL Inspector that I demonstrated (https://github.com/alblue/SILInspector) and written up a post on InfoQ covering the important points of this release