Existing Wording: The variable named in the candidateExpression extension is set to the value of the candidate for use in continuous population of descendant items .

Comment:

I suggest to include a separate section in Expressions to indicate where a name can be used. Also the use of descendant, sibling and child in this context is ambiguous and should be defined further.

Summary:

Include a separate section in Expressions to indicate where a name can be used