I am adding Siri Shortcuts to my navigation app.
I understood in order to use Siri voice to trigger shortcuts, for custom intents, the users have to add voice phrases or record voice for shorctus by Add to Siri button or built-in Shortcuts app; for system intents, the users don't need to do that because Siri already knows all the trigger voice phrases.
But when I say "Navigate to the station using Google Maps", the whole shortcut works without adding to Siri manullay. And based on https://developer.apple.com/documentation/sirikit, I couldn't find any system intents related to Navigation Domain.
Did I misunderstand anything here?
How could Siri and Google Maps exchange intents here without system navigation intents or adding to Siri manually?