src/Pure/Thy/sessions.scala

--- a/src/Pure/Thy/sessions.scala	Thu Nov 04 19:55:59 2021 +0100
+++ b/src/Pure/Thy/sessions.scala	Fri Nov 05 12:05:17 2021 +0100
@@ -856,9 +856,6 @@
           case entries => Some(name -> entries.map(_.info))
         })
 
-    def session_chapters: List[(String, String)] =
-      imports_topological_order.map(name => name -> apply(name).chapter)
-
     override def toString: String =
       imports_graph.keys_iterator.mkString("Sessions.Structure(", ", ", ")")
   }