am 28fb09e0: cherry pick Change-Id: I183ff47e59617b2c17a92b876ca8c8bcc9b45262 docs: add document for the compatibility library

* commit '28fb09e0b27a97e4664c9a31a3c72a067794b4c6':
  cherry pick Change-Id: I183ff47e59617b2c17a92b876ca8c8bcc9b45262 docs: add document for the compatibility library