Where is the tube that transports Freon in your common refrigerator?

Answer 1

Should be in the rear, near the condenser.
In fact the entire condenser is nothing but a tube carrying freon...

Answer 2

All the tubing in a common refrigerator transports Freon - specifically the tubing on the back (non-self defrosting) or the tubing on the bottom (behind the kick cover) in frost free and the tubing molded into the aluminum shell. I have a freezer where nothing shows - the compressor is under a step inside the freezer, the cold tubing is molded in the walls behind the inner shell, and the hot - radiant - tubing is behind the outer shell which feels warm. It is not self-defrosting.

Answer 3

Its the cooling/condensing coil behind the fridge.
Some modern fridges have the coils under the fridge.
If you pull the fridge away from the wall, you'll be able to see the whole layout of the small diameter tubing system from the compressor, through the condenser, into the inside of the cold box and out again back to the compressor.
In the cold box is where the expansion of the liquid Freon and all the cooling action takes place.