Xcode 11 GM vs. Swift 5.1

Hi there,
Now that Xcode 11 GM is released, does that mean that Swift 5.1 is also released?
Or is the version of Swift included in Xcode 11 something other than 5.1?
For instance with the function builders not having gone through evolution yet, is it a part of Swift or only a part of ‘the Darwin flavor of Swift’?
If Swift 5.1 and the version included in Xcode 11 are not the same, does the latter have a name?

It would be awesome with a general update about the state of the language, possibly with ‘next steps’ and addressing of the challenges with non-public language features. :slight_smile: