Hi Edward Wright,
The pin#15 of CYPD2134 on NCP81239 is controlled by CCG2, CCG2 enable it when VBUS provide path shall be enabled. And CCG2 disable it when VBUS provide path shall be disabled. You could test that with plug in Type-C sink and plug out Type-C sink. The enable pin shall be difference.
We do not have plan to release firmware source code of NCP81239 reference design, since there are many customize firmware inside including Quick Charge. If you could like to take a look firmware of CYPD2134, you could get firmware code SDK version after installed CCGx SDK from the link: http://www.cypress.com/documentation/software-and-drivers/ez-pd-software-development-kit?source=search&cat=software_tools