diff -r 46891e209d72 -r cde40295ffd6 src/Pure/General/exn.scala
--- a/src/Pure/General/exn.scala	Fri Sep 22 00:05:11 2023 +0200
+++ b/src/Pure/General/exn.scala	Fri Sep 22 16:11:18 2023 +0200
@@ -78,6 +78,9 @@
 
   /* interrupts */
 
+  def cause(exn: Throwable): Throwable =
+    isabelle.setup.Exn.cause(exn)
+
   def is_interrupt(exn: Throwable): Boolean =
     isabelle.setup.Exn.is_interrupt(exn)