This Whatsit is an Opto Encoder of some kind. I see no manufacturer marking on the board. There is a 6 pin jumper, a 2 pin jumper and an opto sensor on the back. There are two holes near the middle that look like they were designed to allow for some alignment.

I recognized two NPN TIP122 transistors, a momentary switch, a 74C14 Inverter and a 2N2222a.

M-4 REV 3.1 are etched on the parts side. 9530 and DXL-1 94V0 are etched on the solder / opto sensor side.

IDENTITY: Deltronic ticket counter, part of a ticket dispenser.