common/bcp47/* not included in the json extract?

[Kip Cole via CLDR-Users]

I've been working my way through building a lib to support some of CLDR for the Elixir language (https://github.com/kipcole9/cldr), based upon the json sources on GitHub  (which I recognise is not the canonical form).  I notice that common/bcp47/timezone.xml doesn’t appear to be converted to json, and seemingly the other files in the common/bcp47 directory.   Curious if this is a design decision, or some other factor at work?  

—Kip