I can figure out some of it, I think. Big white box is the meter, smaller white box is the main disconnect (OCPD?). Gray box, black box, yellow cable ... ???
Correct on the meter and main disconnect, although it looks like it's only a disconnect, no overcurrent protection.
The grey box is what the PoCo over here use to terminate the supply cable. The red part, as somebody said earlier, i believe is a solid link, but would typically be black and contain an 80A or 100A cartridge fuse.
The small black box is simply a joiner. They're available in one or two pole versions and are quite common where two or more panels are supplied from one service, or in this case to join up the earth (grounding) conductors.
The yellow cable is actually (or should be) green/yellow stripes. It's the main earthing connection. It's connected to the neutral (grounded) conductor in the grey block. From my (limited) understanding of US wiring methods, I believe you use a grounding screw in the main panel to achieve this?
Looking at where the cables come out of the top of the right hand isolator, there seems to be an outer layer of insulation which stops just short, and one of the browns looks black underneath. I'm wondering if they've used a 4 core SWA cable and just sleeved the individual cores, using grey as Earth?