Function watching_binding 

pub fn watching_binding() -> &'static str

__LGX_WATCHING — which component’s When <field> changes: handlers are running (its id among the components that have them, 0 for none): its action has committed, so a trap there is absorbed rather than undoing it. __LGX_WATCH_K is that instance’s key, and __LGX_WATCH_DEPTH how many turns were open when the handlers began (the watching turn’s own entry the last of them).