Add landuse=military to a future version of the schema
Currently the military value danger_area is written as a value of kind to the sites layer.
Of the 92k landuse=military, so few also have military=danger_area that it does not trouble the scorers at https://taginfo.openstreetmap.org/tags/landuse=military#combinations . 67% have no military tag at all.
Usage of landuse=military and military=* are spread evenly across the world; by inference usage of landuse=military without military=danger_area is too (https://taginfo.openstreetmap.org/tags/landuse=military#map , https://taginfo.openstreetmap.org/tags/military=danger_area#map ). it's not a value that is used more commonly by some OSM communities to express that concept than others.
It would add value to a general purpose map style that may want to use the Shortbread schema.
Although military=danger_area is in sites, for landuse=military the "land" layer is an obvious location, as a new value of "kind" as just military This would include landuse=military objects without the tag military and also objects with a value for military tag was not danger_area.