So many good things happened with Swift and open source today.
The project will be hosted on GitHub and will include the compiler, the LLDB debugger, the REPL command-line environment, the standard and core libraries, and code from supporting projects.
There is a LOT over on Apple's new GitHub
New to Swift (and also open source) is the Swift Package Manager
Apple engineers working on Swift will start using the GitHub repos, developing the language out in the open.
So instead of getting a big Swift 3.0 info dump at WWDC 2016 in the summer and then digging into the Xcode betas and adapting, developers can already find an “evolution document” on the Swift site that maps out where the language is headed in its next major version.
One of Apple’s goals for Swift 3.0 is source compatibility going forward so that Swift code that is written may need to be recompiled as the language continues to evolve, but it will need to be rewritten or changed less frequently or not at all.
“We’ll be supporting Objective-C and continuing to evolve it as necessary to fit into this evolving world. We do think that Swift is the language that we recommend for new developers to our platform who are investing for the future and building new apps. We think Swift is absolutely the right place to start. But we’ll continue to maintain, advance, and support Objective-C for as far as we can see