Vacuum Line Identification

Can anyone help me identify this vacuum line? I started out with small plans to replace the radiator and water pump, so I didn't bother to label anything.
Now it's turned into a stroker build, and I am labeling parts late in the game. This is the only thing in the parts box that I cannot identify where it came from.
So far I have removed the whole front clip, cooling system, A/C system, and all engine accessories. I don't see any open vacuum lines or fittings anywhere under the hood.
It appears to have some oily residue and grime on the rubber fitting, and I have even tried smelling it to identify a location. Doesn't really smell like oil or anything though.

The Jeep is a 1991 Comanche, 4.0 H.O. so the engine bay should be pretty much the same.

Thats the CCCV tube. ( Equivalent to a PCV valve) The large end fits on the rear elbow fitting on the valve cover. The small end connects to a vacuum port on the intake.

I think you got it... Thanks for the help.
The current setup looks like it was recently added. I must have pulled it out of the glove box or somewhere like that and forgotten. Just bought the Jeep.
The line is just about the perfect length to go from the PCV valve to the barb on the manifold, which is no surprise.

Looks like you were converted from CCV to PCV, either systems works as they essentially do the same thing anyway.

If the PCV works, I'd keep it. Valveless CCV operates essentially on some undisclosed blend of quantum astrophysics and black magic. In later 4.0's it works pretty well, but tends to build up plaque inside, and it's critical to keep clean. The earlier Renix version works too some of the time, but only if you are very good and eat your vegetables.