Generally speaking, Google's OpenRTB implementation attempts to map Google's protocol to the OpenRTB specification, but not all fields translate exactly. While you can generally expect the data conveyed in the OpenRTB implementation to at least be similar to that of the OpenRTB spec, I would recommend reading through the
OpenRTB guide to see what the equivalent Google Protocol fields are, and then referencing the
Google Protocol guide (or the
Protocol Buffer file) to learn more specifics about how it may differ from the vanilla OpenRTB spec.