Update: Apple has told iMore.com that the release yesterday was NOT a preview release, and instead was an automated build.:
Updated: Apple clarified for iMore that what we thought was a preview release of Swift 3.0 was, in fact, just an automated build. The computer-generated name caused some confusion, but it’s meant as a place where outside developers can submit work in preparation for a preview release of Swift 3.
We have removed the download links form this post.
Apple earlier this week released the first preview branch of Swift 3.0, the major update to their Swift programming language. The official release of the new version of Apple’s open source language is expected late this year. Apple will likely show off the new version at WWDC 2016, later this month.
Development Snapshots are prebuilt binaries that are automatically created from mainline development branches. These snapshots are not official releases. They have gone through automated unit testing, but they have not gone through the full testing that is performed for official releases.
Swift 3.0 is a major release that is not source-compatible with version 2.2. It contains fundamental changes to the language and Swift Standard Library. A comprehensive list of implemented changes for Swift 3.0 can be found on the Swift evolution site.
Swift 3.0 is also the first release to include the Swift Package Manager. While the Swift Package Manager is still early in its development, it supports the development and distribution of cross-platform Swift packages. The Swift Package Manager will be available on both Darwin and Linux.
For Linux, Swift 3 will also be the first release to contain the Swift Core Libraries.
Swift 3.0 is expected to be released sometime in late 2016. In addition to its Swift.org release, Swift 3.0 will ship in a future version of Xcode.
(Via MacRumors)