Normal priority, as it has no use case in 1.5 yet, and may or may not be considered for 1.4 with respect to T3493.

T3574 added the constraintGroup element for conjunction of validators, however, no use case yet existed and consequently, the element was missed when adding the reference tree for generation of the XML cache (T5194). In the context of T3493, a use case was considered. We will make the simple fix here, and consider for backport.