It's specifically around default values.

If you use any language long enough you will think, hey it would be nice to have X. Alejandro (in high-school at the time) thought exactly that and implemented it himself - https://github.com/apple/swift-evolution/blob/master/proposa...

You could almost argue the real feature here is how open the community is to additions like this, and there's no need to wait for people at Apple to do it.