Cairo is an upcoming Windows shell replacement. What exactly does that mean? There are plenty of programs that change the way you launch programs or perform other basic functions in Windows. And Cairo started out as little more than a Windows taskbar replacement. But it’s since evolved into a complete replacement for the Windows shell, with a custom file explorer, favorites manager, and live file previews.

As i quote from the site :
“Cairo is a revolutionary desktop environment for Windows. Our goal is to develop a desktop experience that increases productivity and advances current technology standards. With a focus on stability, performance, and productivity, Cairo is sure to turn a few heads.
Throughout the development process we will be releasing milestones, alphas, betas, and release candidates—milestones marking the furthest from completion and release candidate the closest.
The UI in this image represents a Milestone 1 UI, meaning that we have begun taking all of our UI work and consolidating it towards a final interface. Like Microsoft or Apple, this UI may evolve substantially over the course of its development. The alpha available soon will be a Milestone 1 release, meaning it will mark the first leap towards getting Cairo out into the world. The UI milestones are not necessarily going to coincide with the release milestones.”

In other words, Cairo will be a lot more than a simple Windows skinning program. The shell also changes the way you interact with your data. Cairo is still in pre-alpha, and while you can download a bunch of concept artwork, there’s no working version of Cairo available for download yet. But the team plans to release milestone 1 to alpha testers soon.