My new 230w panel with the fancy MC4 3ft long wires as pigtails, turned out to be those wires are 12 AWG aluminum, not copper, when I snipped them off shorter.
So not too impressed with that. I like the other panels I have/had with a junction box and terminals in it that you attached your own wires. Then you knew what you were getting.
On that, when you buy the fancy 25 ft or whatever long MC4 cables to plug your fancy MC4 panel pigtails to, are they also aluminum? So what is their real AWG value? Phooey. I will stick to doing my own wiring; at least that way I know what is going on.