Help please Identify these GPZ 750 carb fittings

I have a 82 gpz 750. I am about to clean the carbs. I just took the carbs off the bike and found two fittings that kind of look like vacuum fittings but they are on the back (airbox side) of the carbs. These are not the front side vacuum fittings. I have accounted for those. These fittings are between each outer pair of carbs. These were not connected when I tore the carbs down and I can't identify them. Can any of you GPZ experts tell me what they are and where they should be connected? I have tried to attach pics. I hope I was successful. Pic 1 is a shot of the fitting. Pic 2 is a shot of the rack of carbs for perspective. Pic 3 is a shot of my JUST CLEANED and REBUILT spare carbs off an unknown bike that does NOT have these fittings. Please help !

Those are the vent Tees. Install tubing to keep water out. Not sure about your GPz, but the vent tubing on my 81 650 is routed over the airbox shoulders and fitted snug between the airbox & side covers and with the ends open to atmosphere; the left side tubing has a frame clamp.

Ok that makes sense. I remember seeing some clear plastic tubing around the airbox. I didn't see how they were connected and couldn't figure out where they connected around the air box. It makes sense now. Thanks

Also , I notice that the carb slide bottoms on the GPZ are concave and they are flat on the other BS 34s. Is this something only on the GPZs or what?

I'm not very familiar with BS34 carbs or ZX750. The carb parts diagram at Partzilla shows the concavity of the slide, though.

Here's a site w/ a pdf manual & wiring diagrams but I didn't see anything about the slides.
mbsween.bike-night KZ750L3 page . Scroll down & click "The Bible" link.

Note: not applicable to the ZX750, but some of the wiring diagrams are mislabeled in the links.
The 1981 Ltd is an H2, the 82 is an H3, & the 83 is an H4. .... search tags mbsween KZ750L3.