What field does core voltage correspond to in Polaris?

I couldn't find what the core voltage field relates to when modding a bios with polaris. I got a card stabilized at -80 mV (using afterburner slider) at 1250/2220 and want to create a bios so afterburner isn't required to apply changes. I know how to set the core/memory speeds but where does the core voltage modification come into play with the polaris bios editor? Which field should be modified?
Any help is appreciated!