M22 Seal Around Fridge

I noticed a draft coming from the vicinity of the fridge. When I bent down to look for it, I can see light from outside from under the fridge. There is a gap on the bottom side of the fridge that is not sealed. It is a bit more than 3/8" and is present the length of the fridge.

Is this gap intentional to allow air into the unit? Any reason I shouldn't seal it? How would you recommend sealing it?
 
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