Spartan, the codename for what some thought was Internet Explorer 12, is actually a new web browser, which will ship with the upcoming release of Windows 10 this year. Windows 10 will be shipped with a backward-compatible version of Internet Explorer 11 as well – meaning that you can still use Internet Explorer with older hardware/software.

The new web browser will include extension support, separate desktop, and mobile versions. Rumours suggest that it will look and feel very similar to Chrome or Firefox.

Mary Jo Foley of ZDNet reported that Spartan could ship alongside Internet Explorer 11 in Windows 10, due sometime in the latter half of 2015. The purpose of Spartan is twofold, Foley reports: first, as a lightweight alternative to IE, but with the foundation for third-party extensions; and as a marketing “do-over” for Internet Explorer, to do away with Internet Explorer’s legacy once and for all.

Finally, Foley suggests that eventually Spartan could debut on alternative platforms like iOS and Android, much like the Bing search app can replace the search widget on Android devices, for example.

In aggregate, Microsoft’s Internet Explorer is still the most popular browser in the world, holding steady at 58 percent of the user base throughout all of 2014, according to NetApplications. Google’s Chrome is steadily climbing, however, from 16.4 percent to over 20 percent at the end of November. (Opera and Firefox are steadily losing share.)