The apparent scoop also supports details mentioned in earlier reports, including the existence of separate desktop and mobile versions, a lightweight, Chrome-like interface and the inclusion of Internet Explorer in Windows for the sake of compatibility. Whether or not you'll see Microsoft show any of this at its January 21st Windows 10 event is another matter. Neowin claims to have seen an early build of Spartan, and it didn't see Cortana -- while the assistant may show up, neither it nor Spartan itself is necessarily ready for the spotlight.
source: engadget.com by Jon Fingas