What is the configurable option port??
Ah. Its a carrier board that can hold either a blank, a serial port (with lines to the breakout on the board) or the external Wifi antenna connectors (looks to be Hirose UF.L to MMCX). It's only useful to for getting cables into the chassis.
Okay, if we take a look at the e-cycling disassembly instructions, there are some head-scratching surprises on page 26...
a) It has a SATA M.2 and an NVMe M.2 port next to each other (number 3) - Hmmm?!
b) The M.2 Key-E port for Wifi/BT combo connectivity is on the bottom rear (number 5) and would require a cable route to the back between 2 and 3 for the external antennas to poke out
c) The riser for PCIe will bring the PCIe card on top of the SATA/NVMe boards
d) There is a single CPU blower for the heat sink, which sits between numbers 4 and 5.
So right now, in terms of ports and expandability:
1 M.2 SATA
1 M.2 NVMe
1 M.2 PCIe x1 Key E (for the wifi/fiber card option)
1 PCIe x16 port (might be x8 just like the t730)
2 USB 2.0 ports (rear)
3 USB-A 3.1 Gen 1 (1 front, 2 rear)
1 USB-A 3.1 Gen 2 (1 front)
1 USB-C 3.1 Gen 2 (1 front)
Note that compared to the t730, you are losing the internal USB ports and the easy/direct breakout to the M.2 Key-E/PCIe x1 port. If HP releases a fiber card it’ll need a fiber PHY module breakout and a connector cable to reach the option port.