diff -r fdaa17402af3 -r e95b9c9e17ff src/Pure/Tools/debugger.scala
--- a/src/Pure/Tools/debugger.scala	Sun Dec 18 15:50:51 2022 +0100
+++ b/src/Pure/Tools/debugger.scala	Sun Dec 18 16:01:37 2022 +0100
@@ -123,7 +123,7 @@
         case Markup.Debugger_Output(thread_name) =>
           Symbol.decode_yxml_failsafe(msg.text) match {
             case List(XML.Elem(Markup(name, props @ Markup.Serial(i)), body)) =>
-              val message = Protocol.make_message(body, kind = name, props = props)
+              val message = Protocol.make_message(body, name, props = props)
               debugger.add_output(thread_name, i -> session.cache.elem(message))
               true
             case _ => false