This code is also compatible with TinyMCE text editor which is used in several other CMS platforms.
They call this code ICE (Integrated Content Editor) and it is designed to provide functionality similar to a word processor when it comes to multi-author documents.
NYT spoke about this code:
When you’re working in a collaborative environment as we and a lot of journalistic organizations are, you really need that ability for multiple people to touch a piece of copy, and for those changes that everyone has made to be catalogued and archived and shown, so that there’s a record of who’s done what to who, when. No one on the Web had such a thing, because most bloggers, when you think about that, are smaller operations than most newsrooms.
A demo is available here.