diff -r d0a0b74f0ad7 -r bcba32fd89de src/Pure/Tools/build.scala
--- a/src/Pure/Tools/build.scala	Wed Dec 23 23:03:03 2020 +0100
+++ b/src/Pure/Tools/build.scala	Wed Dec 23 23:08:57 2020 +0100
@@ -510,7 +510,7 @@
             progress.expose_interrupt()
             progress.echo("Presenting " + session_name + " ...")
             Presentation.session_html(
-              resources, session_name, deps, db_context, html_context, presentation)
+              resources, session_name, deps, db_context, progress, html_context, presentation)
           })
 
         val browser_chapters =