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Finally a mystery connector that is actually a mystery. My guess would be an aftermarket battery charger, but you would be better off asking in the X150 forum:-
Welcome to the Forum, @Dimopoulos4 I noted that you just joined today. Because I've never seen anything like the photo you posted, my guess is that it's an aftermarket tracker. A closeup photo of the printing on the device would be helpful, as that probably has a manufacturer and part number.
Judging by the legion by the red LED, it is a charger. You would need to remove the bracket to see what the amp rating is. Looks alot more substantial than a trickle charger.
Dimopoulos4, I am a fellow 2009 XKR Portfolio owner a little north of you in Tyler. I mounted a CTEK battery maintainer in my trunk using the same jump-start leads as your device (+ to the jump start post inside the back left side of the trunk and - to the stud left of the spare tire). If yours is a charger and not a maintainer, I'd switch it out for a maintainer so you can leave it plugged in without worry.