Fridges are very good dehydrators due to the simple fact that their back wall is a giant condenser. It is always colder than air in the fridge, which forces moisture in the air to condense there, it then drips into the tray under the fridge and air inside gets dry. Dry air absorbs moisture from the food and the cycle continues.

This is why you store your fresh greens in covered plastic buckets, otherwise they will dry out very fast. And this is why dry curing meat in the fridge works really well. Also if you grow herbs or have excess and want to dry them, chop them, put on a tray and into the fridge, they will dry out in a day or two depending on how much you chopped.