Jeep XD

I was workin on my 90' Jeep Cherokee and theres a sticker on the top side of the firewall on the drivers side. it says XD. I can't find any info. what does this mean. also the people before me who had it must have put on the pin stripes that go down the side. and it looks like it has special stamped on the back sidepanels?? ANY info. is helpfull, Thanks Justin