In the leaked Windows 10 Build 9879, few changes were spotted from the recently released Windows 10 preview build from Microsoft. In the Internet Explorer 11, Microsoft has now added a Smiley button which allows you to send feedback to Microsoft. You can either send a Smile or Frown through this new tool. Microsoft has provided similar feedback mechanism in the past in Office Preview builds.
Neowin reported few months back that Microsoft has all new design for Internet Explorer 12 and it will look a lot like Chrome and Firefox. The main change is that URL bar will now appear below the tab bar, currently URL bar and the tabs bar are on the same line in IE11. Another main improvement comes in the area of extensibility as Microsoft has added support for extensions in Internet Explorer 12.
Source: ITHome