Help with 2014 Mustang GT w/ Cobra Jet CAI

Hello everyone, I have a quick question about something that has sort of confused me. I went from a Boss 302 Manifold w/ Roush intake to a complete Cobra Jet assembly with Intake manifold, twin 65MM TB and the CJ CAI. When I was done installing everything there was a hose that originally attached to the Roush intake that no longer has a place to go and it runs back to the driver side and it looks like into the firewall, I was told its some sort of PVC tubing or something like that and was hold I could just cap it off and be done with it. I have scoured the internet and have found nothing on it and most of the pics I have seen on the install do not even have this hose to begin with except one which it looked like this person literally just attached it to the driver side nipple of the TB to just put it out of the away, can anyone help me clarify what this is and can it be safe to just secure it out of the way?

Thanks very much 08GT500, This really helped me to confirm what I was thinking, a little bit of confidence goes a long way. I plugged it and tied it down to the rest of the tubing routed that way for now. And id like to tell you this setup is NASTY, I am absolutely loving it!!! It's been a long time coming and I am extremely happy with the result! The tube looks to be routed to the intake it is not, its ran to the smaller one that is actually covered, its an illusion, lol.