[OLD SKL 69]

HI everyone. I am finally getting around to restoring a 69 Cutlass(350) and I have a question about the gas tank and lines. I purchased a new stainless gas line for the car. When I got underneath the car to change it, I found an additional line coming out of the gas tank that was cut. Does anyone know what this is for? Is it a return line that is supposed to go back to the fuel pump? Am I missing something else? Any info would be appreciated. Thanks in advance.