diff --git a/mod/forum/lib.php b/mod/forum/lib.php
index 27bdc3404fd..e5ad29139c5 100644
--- a/mod/forum/lib.php
+++ b/mod/forum/lib.php
@@ -925,7 +925,8 @@ function forum_cron() {
 
                 $attachment = $attachname='';
                 $usetrueaddress = true;
-                //directly email forum digests rather than sending them via messaging
+                // Directly email forum digests rather than sending them via messaging, use the
+                // site shortname as 'from name', the noreply address will be used by email_to_user.
                 $mailresult = email_to_user($userto, $site->shortname, $postsubject, $posttext, $posthtml, $attachment, $attachname, $usetrueaddress, $CFG->forum_replytouser);
 
                 if (!$mailresult) {