diff -r 31290f54be19 -r fce2202892c4 src/Pure/General/markup.scala
--- a/src/Pure/General/markup.scala	Fri Sep 17 21:50:44 2010 +0200
+++ b/src/Pure/General/markup.scala	Fri Sep 17 22:17:57 2010 +0200
@@ -239,7 +239,6 @@
   val TRACING = "tracing"
   val WARNING = "warning"
   val ERROR = "error"
-  val DEBUG = "debug"
   val SYSTEM = "system"
   val INPUT = "input"
   val STDIN = "stdin"