format item
% format-modifier* q
In the body of an external-data-entity rule or a external-text-entity rule, %q expands
to the name of the entity that triggered the rule. Anywhere else, including in the body of functions called from
either external-data-entity or external-text-entity rules, %q yields the name of the
currently opened element. In either case, the behaviour of the %q format item may be changed using
modifiers.
%q is a synonym for name of entity in the body of an external-data-entity rule or a
external-text-entity rule; the latter syntax can also be used outside external-data-entity or
external-text-entity rules. Everywhere else, %q is a synonym for name of element.