That's part of what I'm saying.  Right now in develop, we should not be trying to support YAML.  So, you should use readConfigSimple().  The work to support YAML will do the needful, whether that's update readConfigSimple() to readConfigSync() or not.

(I am working on the YAML support.  readConfigSync() is going away, so calling it will cause a merge conflict of sorts. It's better to use the established API (readConfigSimple) than to use readConfigSync() which isn't used by anyone else and which is going away.)