diff -r 9bb16dcb9ed8 -r e36f94e2eb6b src/Pure/Tools/build.scala
--- a/src/Pure/Tools/build.scala	Mon Sep 28 21:14:47 2020 +0200
+++ b/src/Pure/Tools/build.scala	Mon Sep 28 22:22:56 2020 +0200
@@ -411,8 +411,17 @@
           case errs => result0.errors(errs).error_rc
         }
 
-      if (result1.ok)
+      if (result1.ok) {
+        for (document_output <- proper_string(options.string("document_output"))) {
+          val document_output_dir = info.dir + Path.explode(document_output)
+          Isabelle_System.mkdirs(document_output_dir)
+
+          val base = deps(session_name)
+          File.write(document_output_dir + Path.explode("session.tex"),
+            base.session_theories.map(name => "\\input{" + name.theory_base_name + ".tex}\n\n").mkString)
+        }
         Present.finish(progress, store.browser_info, graph_file, info, session_name)
+      }
 
       graph_file.delete