For individual mailboxes they categorize them as a post office. Docks etc. are classified as a Transportation service see [https://www.google.com/maps/place/Costco+Docks/@37.7826597,-121.9760133,17z/data=!3m2!4b1!5s0x808ff2c30321a27b:0xa81bd313b0a63538!4m6!3m5!1s0x808ff300599ab62b:0x62050ddb2df6fd2f!8m2!3d37.7826555!4d-121.9734384!16s%2Fg%2F11vm55bg7l?entry=ttu] .
Manholes and the rest are classified as City Transportation or whatever the troll wants to select incorrectly to rack up their points. .