Continuing the discussion from Introducing Ghost 2.0:
The Ghost blog post describes it as, “a portable JSON-based document storage format that can store blocks of content and translate their output into a variety of formats such as HTML, RSS, AMP, NewsML, or just about anything else you can think of.”
On the README, “Mobiledoc Kit (beta) is a framework-agnostic library for building WYSIWYG editors supporting rich content via cards.”