+# Things I tend to forget. on MAIL_HOST, daemon runs with /etc/exim4/my.conf,
+# which gets generated from update-exim4.conf -d /etc/myexim4
+# which has log path
+# log_file_path = /var/log/exim4/my%s
+#
+# so, normal mainlog is non-daemon, which delivers to the daemon.
+