Coolbox/ refrigerator box?

[Morganic]

Decided to give my van a clean out before winter
Noticed a small amount of yellow liquid which seemed to be coming out of the base of the cabinet holding the water tank and gas bottle holder. Couldn't detect any smell.
No evidence of any leak there but wondered if it could be from the coolbox. Does it have a vent and if so where is it?
Might be someone's spilled something but I don't think so.
Have put coolbox on full to see if it's working ok
Anyone any ideas?

 

[jts46]

Cool box (refrigerator) to far away i would think. Could it be rust from bottom of gas bottle mixing with a little dampness?