That is a Dual Combo creator PCB. They are for creating a dual combos using 2 NostalgiTone Singles.
Check your bags for just the 2 standard NostalgiTone 3PDT wiring boards and a pair of ribbon cables.
Note: The 3PDT wiring boards must be the NostalgiTone variety as shown above and not the older “Legacy version” which would obviously not work with the 6-pin ribbon cable.
I did find a 3 pack of the proper wiring boards that I maybe ordered so I’ve got that covered. All other unbuilt boards in my inventory seem to have appropriate switch boards and the one in the picture has no home lol. No action requested, just wondering.