Found 4feet of wire under the door jam

This AM I was removing the door jam on the drivers side  of my 94 to put some lub on the E-break. Upon pulling the Cover of I found this heavy#4AWG PUNCH POWER CABLE marked ROCKFORD FOSGATE. When I pulled it out of the way it came out in my hand. Somone has cut a 4 foot section out of what I think must be the grounding loop. I dont know a lot about fiberglass vehicles but common sense tells me "this ain't good". So my question to all of you is  what do you think? I don't seem to have anything that is not working properly but will I have problems in the future?

was it maybe a wire for a stereo system?

I would try to find the rest of it just to be on the safe side....someone had a powerful amp system in there at one time or another.

Just guessing....sounds like maybe the previous had a aftermarket stereo and/or sub woofer and amp. installed which may have been removed before the car was sold ?? Do you have the factory stereo now?  It's nothing I'd worry about if everything works....anything labeled "Rockford Fosgate" woudn't be factory.

Thanks, sterio was my first thought but it has the original radio. From the location of the cuts I would think that someone might have removed it in a hurry. I couldnt find any other locations with the same wire. So mistry solved. Again Thanks.  Hal