Also it is in the join between the ute and van tray section, heaps of people don't put this back in during their resto and they end up rusting. Took me ages to scrape out/wire wheel the old cracked stuff. I think the stuff is hydrophobic (i think that's the right word) it will suck out any moisture in the joint on drying.

plus its impossible to spray paint into the gap so the material will never be properly protected.