in management-loglevels-log4j2/src/main/scala/org/apache/pekko/management/loglevels/log4j2/LogLevelRoutes.scala [133:140]
def classicLogLevelName(level: ClassicLogging.LogLevel): String = level match {
case ClassicLogging.OffLevel => "OFF"
case ClassicLogging.DebugLevel => "DEBUG"
case ClassicLogging.InfoLevel => "INFO"
case ClassicLogging.WarningLevel => "WARNING"
case ClassicLogging.ErrorLevel => "ERROR"
case _ => s"Unknown loglevel: $level"
}