Product review (5 stars): Fixed my leaking KitchenAid
This was the fix for the leaking freezer compartment in my KitchenAid KBSF20EVMS8 refrigerator, which is made by Whirlpool.  It had the classic symptom where ice would start building up on the floor of the freezer, then a few days later it would start leaking water.

Installation wasn't too bad, just remove the back panel, remove the rubber duckbill valve, and remove the gutter that the duckbill valve drips into.  Then, install the gasket grommet over the drain spout where the duckbill valve was, and snap this into place.

One caveat: typically when your fridge has this problem, there will be ice built up above the duck bill valve.  So you will need to empty the fridge and leave it turned off for a day or so to let the ice melt, otherwise the problem will persist despite this fix.  Once you have done this, the new drain will prevent it happening again.