The arrows point to visible daylight. The sink drain had frozen and busted allowing the sink water to run out on the floor. Apparently duct tape is not effective for this type of repair either. The sink water just drained though the holes and onto the ground. Also, the drip pan under the fridge was never emptied and so the floor there was completely rotten. It can barely be seen to the left of the partition on the far left side of the kitchen picture.