When I reply to a bug report via the "x - Provide extra information"
option, reportbug does not include the In-Reply-To/References headers,
which means that the reply breaks mail threading, which is likely to
help recipients of the mail find other messages in the thread and
having this information missing will be annoying to maintainers.

Here is an example of a reply where I recently discovered this:

   $ cat /tmp/user/1000/reportbug-pulseeffects-backup-20210422090628-07ud97t0
   Content-Type: text/plain; charset="us-ascii"
   MIME-Version: 1.0
   Content-Transfer-Encoding: 7bit
   From: Paul Wise <pabs@debian.org>
   To: Debian Bug Tracking System <986733@bugs.debian.org>
   Subject: Re: Support for pipewire
   X-Reportbug-Version: 7.10.3

   Package: pulseeffects
   Followup-For: Bug #986733

   ...