BubbleGuppies
I found satellite imagery that shows the new construction and now I feel stupid. Seeing that it is a collection of private mailboxes I think it should be tagged as "amenity=letter_box". The wiki page isn't super clear (https://wiki.openstreetmap.org/wiki/Tag:amenity%3Dletter_box) but the wikipedia page as examples of banks of letter boxes. https://en.wikipedia.org/wiki/Letter_box