What does the "Set Zero" button actually do? ie, does it send a G92,

What does the “Set Zero” button actually do? ie, does it send a G92, or a G10, or some GRBL realtime command?

I tells the system that current position is now home (z,y,z)=(0,0,0)
This gets reset when you do a proper homing using your limit switches…

IDK the exact command, but it’s in the GCode command reference somewhere!

G10p2 I remember

I was afraid of that. Macros to the rescue.