The final and block attributes are #all or a whitespace list of method tokens,
but the admitted tokens depend on the component: element final is
extension/restriction, element block adds substitution, complexType final/block
are extension/restriction, simpleType final is list/union/restriction. The
tokens were parsed leniently (unknown ignored, substitution admitted
everywhere), so final="substitution" on an element, a misspelled or miscased
token, or #all mixed with other tokens was accepted.
The list is validated against the component's exact set; finalDefault/
blockDefault (the wider schema-level value space) and foreign attributes are
left alone.
XSTS: invalid schemas accepted 580 to 537, valid schemas rejected held at 72,
instance buckets unchanged.
