Usage of behavior-with-declaration with temporal operators

The OSC2 grammar definition allows composition to have a behavior-with-declaration, which can contain constraint declarations, modifier applications and until-directives. However, chapter 7.3.13 only talks about passing parameters to composition operators similar to methods to constrain them, but nothing about using keep, let alone modifiers or until directives. So are constraints, modifiers and until allowed in this place? If yes, we should describe what to use them for and how to do so. If not, we should change the grammar so these things are not considered syntactically correct.