From: Alice <alice@example.org>
To: Daniel <daniel@example.org>
Subject: grand-child message
Message-ID: <B01-grand-child@example.org>
In-Reply-To: <B01-child@example.org>
References:  <B01-child@example.org> <B00-root@example.org>
Date: Fri, 17 Jun 2016 22:24:41 -0400

This has the references headers in the wrong order, with oldest first.
Debbugs does this.