Check the traces on the PCB, that's not a HDD connector at all. it's a 68000 PDS Passthrough for another PDS device!

Check the board for copyright & mfr. designation!

Methinks it's something on the order of a MacSnap Accelerator and that the missing Hyperdrive 2000 Interface Card was the device hooked up to that passthru 68k PDS.

Just a guess . . . based on a cursory inspection of the PCB traces.

Methinks it's time to pull out the ole' continuity tester!