Context element, so either segment or scenario.
CyclesAllowed attribute value, so either "any", "undirected" or "none".
Value of (item declaration) attribute xbrli:periodType, so either instant or duration.
Use attribute value, so either optional or prohibited.
Variety, so either List, Union or Atomic.
Well-known standard label roles.
Well-known standard reference roles.
Classes that are common to the DOM and model packages, typically "enumerations".