Microsoft is rumored to be working on a new browser for Windows 10. So new, it may not even be called Internet Explorer.
It will still use Trident, Microsoft’s web rendering engine, so it’s likely to be more about changing the user interface (to be more like Chrome) and brand than anything fundamental. However, the break is supposedly big enough that Microsoft will include both this new browser and the existing IE11 “just in case” for Windows 10.
The new browser’s primary feature is to be lightweight and fast loading; hence its code name “Spartan” within Microsoft. This is the browser designed for all devices: PCs, tablets, phones and maybe even smaller.
It will probably have native app support – similar to extensions – and I expect Microsoft to eventually port it to Android and iOS.