This ?? (see picture below)
If that is what you are mentioning, it is a weep hole.
It will allow the camper roof to breath.
For how we are building the camper roofs these days, we have found it is not necessary.
We use different insulation here at FWC now in the camper roof (white styrofoam boards), instead of the spun fiber batting (fiberglass) and a good, breathable marine style headliner.
Most customers with allergies and respiratory problems were worried to have a breathable headliner inside the camper and the fiberglass insulation behind it. That fiberglass insulation was also coming to us with a strange smell in it from time to time.
For the past few years, we have not been building the FWC campers with the weep holes.
There are probably about 1000 FWC's running around out there now without the weep holes and we haven't had any problems.
Working great.
We were more worried about the weep holes letting water in (leaks), than we were with the weep holes letting condensation out.
The less holes in the camper roof, usually the better.
Trust me, if we were having black mold issue two things would have happened a long time ago.
One, we would have fixed it ASAP.
Two, you would have heard about it on this forum instantly.
One can spin it either direction (laughs).
We can make them sound like the best things since sliced bread, or we can tell you they are not necessary.
Nothing to worry about.
.