Logger.critical

You're seeing just the macro critical, go back to Logger module for more information.
Link to this macro

critical(message_or_fun, metadata \\ [])

View Source (macro) (since 1.11.0)

Logs a critical message.

Returns :ok.

This is reported as "error" in Elixir's logger backends for backwards compatibility reasons.

Examples

Logging a message (string or iodata):

Logger.critical("this is a critical message")

Report message (maps or keywords):

# as keyword list
Logger.critical([something: :reported, this: :critical])

# as map
Logger.critical(%{something: :reported, this: :critical})