Micromoog Mystery PCB 980-040-121

I’m new, so I apologize for starting out of the “gate” with two posts.

Moog PCB 980-040121 was previously located near the fine tune control of my Micromoog. It is likely that I am not the only person who needs to know its function.
The Micromoog/Multimoog service manual .pdf that I have does not document this PCB.

It contains three resistors and a Texas Instruments LF321N op amp.