There is a leaking o-ring Inside the pump's top cover,when it leaks it spills out the "vent" Pictured.To repair this it requires the top half of the pump to be removed and rebuilt.Most places won't prefrom this repair on the engine.
If its not making a big mess then I wouldn't worry about it,nothing major will be affected/damaged.Ifs its dripping on the ground or the fumes are entering the car then have it fixed.This is only my 2 cents :wink:.
Add your location to your profile,others in your area may chime in and point you to a shop near you :wink: