Ok, don’t take this as gospel without checking it out first but, a fridge works by taking heat from the inside and transferring it to the outside. Much like a car takes excess heat from inside the engine and disperses it outside via the radiator, the heat from the inside of the fridge gets dispersed outside in one of two ways:
Via a metal grid on the back of the fridge
Or through tiny pipes within the casing
So, if the back of your fridge looks like this, you have the pipe work in the sides, back or elsewhere within the casing so should either leave it be, follow the precautions mentioned elsewhere in this thread before drilling or go for it and take a chance.
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On the other hand, if the back of your fridge looks like this, then this is where the heat comes out and there aren’t any pipes hidden in the casing
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