|building = proposed
|Using this tag is discouraged, use nothing instead.
|Rendering in OSM Carto
|Used on these elements
|Tools for this tag
This tag combination is sometimes used to tag inexisting, only proposed buildings. In addition to all problems related to mapping proposed contructions this tagging scheme is creating problems for data consumers as Key:building have highly varied values and it is unreasonable to expect special handling of this value.