The liquid freon (still hot, by the way) is piped from the condenser to a filter/dryer cylinder. The filter/dryer is a canister (about the size of a beer can) full of desiccant; any moisture (which would cause corrosion) is removed by the desiccant. On some systems (including Saab’s) the filter/dryer also has a small glass viewing portal (about ¼" diameter) which allows you to see if bubbles are in the liquid stream. Bubbles generally indicate the presence of vapor (gas) in the liquid, which implies that more refrigerant needs to be added to the system.
The filter/dryer is located in the aquarium, at the back of the engine compartment.