In my personal opinion that plastic part does not belong to the Crossfire. It appears to me to be a port cover for something electronic.

Given the clue that a technician worked on the car for something electronic it very well could have come from a scanner device he was using. Nothing like that on the Chrysler Starscan, or DRB III, but the Starmobile has similar but different port covers. It could very have been some other brand scanner.

There could be another possiblity, maybe the technician was using some kind of portable worklight/power pack with a Lithium Ion batteries, and that was a cover for the recharge port which may have included both a round plug and a USB connection.