As part of Chaplin's jap code, what events are prefixed! I mean?

I saw that these events were scattered throughout the Chaplin code example, but there is no explanation in the documentation or source. This seems to mean that it is a global event that triggers an action. It's right? Are they just a convention or are they somehow applied?

# Handle login
@subscribeEvent 'logout', @logout
@subscribeEvent 'userData', @userData

# Handler events which trigger an action

# Show the login dialog
@subscribeEvent '!showLogin', @showLoginView
# Try to login with a service provider
@subscribeEvent '!login', @triggerLogin
# Initiate logout
@subscribeEvent '!logout', @triggerLogout