In C, ADBC consists of a self-contained header. The header is reproduced in full here, and is intended to be self-documenting.

From apache/arrow-adbc commit f044edf5256abfb4c091b0ad2acc73afea2c93c0:

.. literalinclude:: ../../../../format/adbc.h
   :language: c
   :linenos:
   :lineno-match:
   :lines: 166-1123