Microsoft’s new Spartan rendering engine.
“I watched Justin Rogers, one of our engineers, press “Enter” on the commit that forked the engine—it took almost 45 minutes just to process it (just committing the changes, not building!). When it completed, there was a liberating silence when we realized what this now enabled us to do: delete code, every developer’s favorite catharsis.”
“In the coming months, swathes of IE legacy were deleted from the new engine. Gone were document modes. Removed was the subsystem responsible for emulating IE8 layout quirks. VBScript eliminated. Remnants like attachEvent, X-UA-Compatible, currentStyle were all purged from the new engine.”