public String getVar() {

        return (String) getStateHelper().get(PropertyKeys.var);

    }
<p>Return the request-scope attribute under which the data object for the
current row will be exposed when iterating.  This property is
<strong>not</strong> enabled for value binding expressions.</p>

 @return he request-scope attribute.
primefaces/src/main/java/org/primefaces/component/patch/UIDataPatch.java