The Microsoft Display Dock was designed for the Microsoft Lumia 950 but because it supports USB Power Delivery, it can be used to charge other phones like the LG G5.
Using Granite River Lab's Power Delivery test software we are able to see the communication between the Microsoft Display Dock and the LG G5.
The Microsoft Display Dock is pretty basic in that it only declares support of 10 watts charging using 5 volts @ 2 amps.
The Microsoft Display Dock also supports DisplayPort Alternative Mode over USB Type-C.
The LG G5 simply requests 5 volts @ 2 amps from the Microsoft Display Dock.
We can then confirm from the following oscilloscope screenshot that the LG G5 is pulling 5.3 volts @ .3 amps from the Microsoft Display Dock while its battery is well charged.