Euro QV vacuum question

I was tightening some coolant hoses under the plenum last night, and noticed a vacuum hose with a bolt in it. The other end is plugged into the bottom of the throttle body. See photo. There are two coming from under the body, and one is already connected to the warm-up regulator. The other one is capped off.
What should this be attached to? It ends near the WUR.
Thanks,
John

The warm -up reg should have 2 vacum hoses to it (1 on thetop, 1 on the side/bottom)...one for idle vacum and the other to richen mixture (lower pressure) for full throttle power.

Check it out to see if the wrong Reg might be installed leaving an extra V-line.

Only one vacumm connected to mine- on the top. I pulled it (WUR) off last night during the coolant hose tightening. On the bottom of the WUR is a small (1/8") hole with what looks like a ball bearing at the bottom. Almost like a purge valve or something. I'll try to remove again and photograph.

Do both vac hoses you mentioned for the WUR come from the throttle body?

>>Do both vac hoses you mentioned for the WUR come from the throttle body?<<

Yes they do John, 1 large hose, 1 small.

Hmmmm- the smaller of the two is disconnected.
I'll try and find out if this is the wrong WUR for my car. Weird. I wonder if a US WUR was installed, or a US throttle body? I'll have to look through the records. There seems to be different (one or two vac hoses) WURs on the Ferrari UK site for parts- depending on the country and year.
Thanks for the info.