Existing Wording: In theory, this expression can rely on the values of the answers to child questions or on variables calculated from the values of other questions, however such questions would have to initial values. (See the discussion below on dependencies.) Most typically, it will draw on launchContext and itemContext to populate questionnaire elements based on information available from outside the QuestionnaireResponse.

Comment:

Indicate that "launchContext" and "itemContext" are extensions by adding the word extension

Summary:

Indicate that "launchContext" and "itemContext" are extensions by adding the word extension