The LG G5 comes with a Qualcomm Quick Charge 3.0 enabled charger but still supports USB Power Delivery charging. To prove this, we used an oscilloscope and software from Granite River Labs to capture the USB Power Delivery Protocol transactions going between the LG G5 and the Google Universal Type-C Charger 60W.
In general, the LG G5 can be charged using USB Power Delivery at 15 Watts (5 Volts @ 3 Amps) or 18 Watts (9 Volts @ 2 Amps). However, the Google Universal Type-C Charger 60W only supports 5 Volts, 12 Volts, and 20 Volts rails so actual charging with the LG G5 is done at 5 rather than 9 Volts. The results is that the Google Universal Type-C Charger 60W only charges the LG G5 at 15 Watts (5 Volts @ 3 Amps).
Thanks to Benson Leung for providing various corrections and clarifications on this review.