Unknown Part For '78 Lincoln

I recently changed the Ignition Control Module on my 1978 Lincoln Continental. This part was mounted onto the ICM and plugs directly into it. I have gone to the Lincoln/Ford dealership, visited multiple auto part stores, and searched everywhere online, but I cannot figure out what the name of this part is called or it’s purpose. If anyone is familiar with older Lincoln’s, I would greatly appreciate it if you could tell me what this part is and where I can find a replacement. Currently, the car is running and driving without it, but I’d still like to replace it as it must have some importance. The numbers on the part in question are D8AE-12A265-BA. Below those numbers on a separate line are 75-566 (not sure if that is supposed to be a part of the first set of numbers).