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. There have been no new previews or releases, and the links have been removed. We've likewise updated this story.
Developers interested in Swift, Apple's programming language, can now download the first preview build of Swift 3.0. This is set to be a major release of Swift when it officially arrives, and is meant to mature the language. Developers can download the preview now from Swift.org.
Swift 3.0 will be the first release of the language to include the Swift Package Manager, which will support the development and distribution of cross-platform Swift packages. This version will also not be source-compatible with Swift 2.2, but as noted on the Swift GitHub repository, the goal is for future versions of Swift to be source-compatible with 3.0.