Add "send_all_email_to" setting see BT#12972

main/install/configuration.dist.php

@@ -473,4 +473,12 @@ $_configuration['agenda_legend'] = [
 //$_configuration['allow_career_diagram'] = false;
 // Allow scheduled emails to session users. See class ProgrammedAnnouncement
 //$_configuration['allow_scheduled_announcements'] = false;
+// Add the list of emails as a bcc when sending an email.
+/*
+$_configuration['send_all_email_to'] = [
+    'emails' => [
+        'admin1@example.com',
+        'admin2@example.com',
+    ]
+];*/