The following is a great post with a great overview to the Developer Tools found in Internet Explorer 12.
- Clean, modern, user interface.
- New UI Responsiveness, Memory, and Emulation tools.
- DOM Explorer, Console, and familiar tools are updated to enable an easier and faster workflow
In previous versions of the dev tools, there was a menu. Some items have moved to various parts of the IE F12 developer tools. For example, the Browser Mode options that were once part of the menu are now the Emulation tab. Let’s take a quick look at each tool in the toolset and what it can do for you.”