You could say the Salvatorian Clause in contracts is like exception handling: a "catch (all)": even if some clauses in this contract are illegal, the remaining contract stays in place.

Logically, this actually doesn't make sense strictly speaking because the sentence creates a paradox: doesn't it make clear whether it includes itself or not, and each reading ends up in trouble. There is a "tradition" in law around the world to accept the only benign reading of such clauses, which I always found funny given that in all other ways lawyers adopt the most adversarial mindset imaginable.