Actually, -ck abandoned his development of cgminer years ago. Kano is the sole remaining active Primary developer of it and has applied a slew of updates to it since -ck left the project. BTW, Kano wrote the entire API for cgminer. His repo is
https://github.com/kanoi/cgminer The API info is under API-README.
AFAIK Bitmain (and most other makers) uses the cgminer API with no additions of their own.