One of the signature features of Windows 10 is a new default Browser, Microsoft Edge. Although its EdgeHTML rendering engine is based on the familiar Trident engine that has been part of Internet Explorer since its earliest days, the new engine is built with the goal of being highly interoperable with modern web standards.

The Internet Explorer development team says it removed 220,000 lines of code when it began modifying the Trident engine for EdgeHTML. That major pruning was essential to rid the new browser of compatibility baggage that contributed to Internet Explorer’s poor reputation in the web development community. With that step out of the way, they added new and useful features, such as integration with Cortana, a new reading list, and the ability to annotate and share webpages. More importantly, the new browser offers excellent support for modern web standards and better interoperability with other modern browsers.

Microsoft Edge has been developing at breakneck speed since its first public appearance (with an incomplete feature set) in an April 2015 Insider preview release. The initial (July 2015) Windows 10.

Current Branch release included Edge version 12; Windows 10 version 1511 is a major update
that takes Edge to version 13.

If you’re wondering what happened to Internet Explorer, you’re not alone. Many line-of-business apps in enterprise deployments require Internet Explorer. Some apps require versions older than Internet Explorer 11, which is the only supported version as of January 2016.

The good news for IT pros in those challenging enterprise environments is that Internet Explorer will continue to be available in Windows 10, with Enterprise Mode available as a feature for ensuring that older apps work properly.

Source of Information : Microsoft Introducing Windows 10 For IT Professionals