I am hearing that the builders are putting the homes so tightly together on these zero lot line homes that the city requires these type vents instead of soffit vents. This is a 10 month old home and the vents are rucked really bad. They seem to be performing their function.
As Steve said it is a roof vent. Or as described at the manufacturer’s website “on-the-rooftop intake ventilation”. A shorter term, "rooftop intake vent’.
In some areas (like the mountain areas around Boulder), continuous soffit vents are no longer allowed for fire danger reasons. I believe this is what they’re using instead.
As I understand it. (not really certain but a client told me this one) Some cities that have the zero lot line homes as this one did, do not allow soffit vents on the sides where the home is one boundary to the yard. Something to do with for instance BBQ smoke venting into the attic space. That sort of thing. But then I see this on other homes that are not zero lot line.