x1 (condition) is the condition for an exception/'else' case of rule x2 with its own rule/outcome/consequent x3.
An exemption often is the sumti-raised subject of an exception, but usage of the English word varies and it may simply be the exception itself. If the consequent of x2 (which is not necessarily explicitly specified by this word) is a a strict, nonfuzzy binary by nature and the law of excluded middles is assumed, then x3 is assumed to the complement thereof. See also: "javni", ".ifle", "da'ai'a". Emphasis here is on the condition that causes the 'else' case (rather than the complement, which is the condition of the implicit 'IF' statement); it is usually used as a practical afterthought.