[quote:29a0kt1g]
The team behind the engine has forked Trident into two components that will result in a new .DLL when the browser ships.
The forking of Trident, copying off the code base so there are two version, is a strategic move to have legacy support no longer impact modern webpages. How it works, per our internal sources, is that if a page calls for IE to render in a compatibility mode, this will cause the older, more resource intensive Trident engine to display the page. But, if the webpage does not call for compatibility mode, then the updated IE12 Trident engine will handle all of the lifting.