A building's feature id in the map's vector tiles, the same in every tile and zoom level that holds it. The tiles split a building of several heights into parts, which the plugin draws, colours and lights up as one, under the id of the building's whole outline. A landmark's id is a number taken from its position, the same in every session.
A building's feature properties, such as height and group, its whole outline's when it comes in
parts. A landmark's position, as [longitude, latitude].
A building of a Buildings3D or a landmark of a Landmarks3D, as their user events report it.
Example