What are these and why are they leaking

If you ever go to the auto parts store for a new ECU, I suspect your ECU will be a 5 pin with a dual ballast resistor.
They will offer you a 4 pin. It's a drop in replacement. It will just use one of the ballast resistors.
My advice is to try the new box in the parking lot.
I've have gotten junk in the last couple of years that would not even run my daily driver.
I found this two weeks ago and gave it to the manager at my local parts store since his are blue and now junk.

HEI in Mopar ECU casing