Hi Ian,
Just as I have told you, WRAPEN is just for the internal usage, customer can't use it.
Temperature sensor is connect to the ADC from internal, so I don't think you can test the temperature sensor voltage on the ADC pin.
Please also check this register:

When you select the temperature to channel0, it won't select the ADCn_0 pin, so actually, to customer, there has no output pin for internal temperature sensor.
Wish it helps you!
Have a great day,
Kerry
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------