A small native iOS feature that supports customized recognition (eg recognize an apartment buzzer or specific laundry machine chime).
I don't have an iPhone to experiment with so I don't know what all is supported, yet I could see this being used to pass specific sounds only through noise cancelling (or rewrite them to use a different chime), or by leaving your phone somewhere out of hearing range to "tunnel" to a notification onto your desktop (if that's supported).
