Ios Push sounds

Hey. Does anyone know what the available syntax is for a ios push of the sound attribute? For example;

it uses name: “default” What are other options that I could use?
it uses critical: 1? I don’t know what that means
and finally it uses volume: 1.0 which represents 100% volume. But the sound documentation Sounds | Home Assistant Companion Docs doesn’t mention much else.

does anyone know?

https://companion.home-assistant.io/docs/notifications/notification-sounds/#pre-installed-notification-sounds

Critical means the alert will ignore your phone’s “do not disturb” mode if it is active.

Thanks very much! You wouldn’t happen to know what the number represents after critical do you? and if that value can be changed?