The first black box is the junction box for the 7 pin connector. Behind will be the inverter which has a large fuse on the red positive line with a black cover. The inverter also has a regular 110v plug which is coiled up and not used. Looks like you can just see the light grey phone line that connects the inverter to the remote switch in your galley area. The
12V disconnect switch/relay is here (the one you can hear click when you put your battery in store mode). The are positive and negative bus bars that collect various
12V wires. There are various lengths of spare cable bundled up also . It's a rats nest in there!
Picture from my 27FB International below.