Repeats... once per "questionID" that the target is linkd to.

The element is named using the questionID of the question on which the target depends. The value of the element must be a zero-based number, indicating the required answer.

Links have no useful meaning in the context of a "text" or "textarea" question-type.

If no questionIDs are specified, then all links are removed, or there are no links in place.