src/Pure/General/markup.scala

   val REPORT = "report"
   val WRITELN = "writeln"
   val TRACING = "tracing"
   val WARNING = "warning"
   val ERROR = "error"
+  val RAW = "raw"
   val SYSTEM = "system"
   val STDOUT = "stdout"
   val EXIT = "exit"
 
   val NO_REPORT = "no_report"