Inside Fuel Door, Whats the Hose for?

[CKtour98]

If you open the fuel door, on the inside right theres a hose that connects into the "box" section of the housing....whats this for?? Vapour or overflow for the gas??

Need to know asap! thanks guys...

[CKtour98]

Got it, was able to trace it underneath the car and see it runs into the charcoal box. seeing how it was just vented to the atmosphere basically in the stock setup, I'm just going to ziptie it to the neck and screw the door on with the 1/4 panel lock tabs. Should have just done this in the first place as I nicked my car and the door a few times trying to get the dang stock plastic piece back in ! Grrr