If something is liberatory, it gives you a sense of freedom and relief. If you're bored waiting for something to end so that you can go home, the signal that you can finally leave is liberatory.
Liberatory comes from a Latin word liberare meaning "to set free." This is also where we get words like liberation and liberally. It can refer to something that gives literal freedom, like a clock chiming when it's time to go home, or metaphorical freedom, like a book that gives you a new perspective.