Fuel Plumbing question, Newbie, fuel fitting ?

[DonImbimbo]

What would this type of fitting be used for?

184075

I know one end is the push-to-lock fuel (in this case 1/4 inch) but what is the "barbed" end supposed to interface with? Confusing that it has an 'O' ring.

Clearly I'm a newbie when it comes to fuel system plumbing.

Just for background:

I bought the Factory Five in tank EFI option
I also have the complete Holley Sniper install kit that came from Blueprint

[Mastertech5]

The other end is a hose barb. Used for fuel return at the tank unit. Use appropriate size hose and a clamp. The o-ring is for a better seal in the hose. You can also use the PTFE plastic line that is pressed on but you need a special tool to do it.