Frank forked the CSL schema for his work on multilingual and law styles (http://citationstylist.org/). To make maintenance easier I turned this into an extension schema that uses the official schema as its basis, redefining only those parts that needed changing. Ultimately Frank and I would like to merge as much as possible of this into the official schema, but that might take a while. I want to stress that while Frank and I work on this, the extension schema is a fork independent of the CSL project. We in no way promise any kind of cross compatibility with official CSL styles, and the extension schema may be changed at a whim's notice.