OGC Definitions Service (Beta)

http://www.opengis.net/def/nil/ogc/0/

http://www.opengis.net/def/nil/ogc/0/

label http://www.opengis.net/def/nil/ogc/0/ more like this
type
Collection
is primary topic of &_format=html
same as
OGC Nils 0
same as 0