The IBC is going to be on the left side, with 48V input power going to it.
I'll be making some firmware tweaks to the IBC (adding a communications interface so the main board can do remote on/off, query voltage and current and temperature, etc), so I need SWD and UART to it.
Then the main board needs the big 12V power cable to the IBC plus the control cable with I2C, output enable, and 3.3V standby.
Supervisor MCU on main board needs SWD and UART.
Main MCU needs JTAG and UART.
And then the FPGA needs JTAG.