Looking at the symbols I see a 12V or 24V battery on the left (J1) and right from that there is a put power connector (J2) in. So you can solder two wires in or use a neat powerconnector in.
If it is safe to do this I really don't know.
Two RB760iGS (hEX S) in series. One does PPPoE and both do IKEv2.
Running: RouterOS 6.46Beta59 / Winbox 3.20 / MikroTik APP 1.3.7
Having an Android device, use https://github.com/M66B/NetGuard/releases (no root required)
i guess its made for version for another enclosure(unified PCB save lot of time in production, generally).
right was for different power socket/jack.
left one i guess for backup battery of some kind.
aside generic, obvious uses, both are handy if you build dense, caseless RB setup(common in small-ish ISP datacenters).