The locatable class here does not contain the Archetyped class in the reference model; it will probably do so in future as a minor version of this schema, which will be backwardly compatible. This is to allow the development of suitable access control measures to become represented in this class in the future. The archetype id is copied (in the reference model specs) to the archetype_node_id and so is present in the data in this attribute of locatable. This maximises the match between Xpath and the archetype paths. The appropriate display (is_rotated) is set in the archetype, as is the number of heading rows if the table is rotated