Adamant1
I was wondering about this myself. It appears that they are mail lock boxes with secure boxes for 11 houses each and a slot on the top left side to stick out going mail in. It would be interesting to know if the out going mail slot can be used by anyone or if an old man in a bath robe will come running out of a house welding a rolled up newspaper. Even if not, I would assume the boxes are meant for the residents in spirit at least if not legally also. So I would stipulate that amenity=letter_box would probably be more appropriate. Especially they seem to be more for drop offs to specific customers then anything. Also, a few of them don't seem to be there on the ground. So they should probably be reviewed anyway. 