At this week's Microsoft Convergence 2015, Microsoft announced that Project Spartan will replace Internet Explorer as the default browser in Windows 10.
Their Chief Marketing Officer Chris Capossela broke the news, “We’re now researching what the new brand, or the new name, for our browser should be in Windows 10. We’ll continue to have Internet Explorer [for enterprise compatibility purposes only], but we’ll also have a new browser, which is codenamed Project Spartan. We have to name the thing.”
A Microsoft spokesperson further assured IE users: “Project Spartan is Microsoft’s next generation browser, built just for Windows 10. We will continue to make Internet Explorer available with Windows 10 for enterprises and other customers who require legacy browser support.”
Source + Zooey