Alloy. I thought the ABYC rule is catastrophic fuse not more than 7 inches from the battery terminal. There are a lot of points in that diagram where a random event could short the battery before the circuit protection.
Any ungrounded conductor that's not in an enclosure/conduit and is longer than 7" needs protection
Protection can be:
max 40" away if the cable is protected and connected to a power source other (like a disconnect) than a battery
max 72" away if the cable is protected and connected to a battery terminal