[Pkg-mailman-hackers] Bug#995898: mailman3: dmarc_mitigate_action wrap_message drops Cc

[MGC]

Package: mailman3
Version: 3.3.3-1
Severity: normal
X-Debbugs-Cc: hgasuser at gmail.com

Dear Maintainer,

I am using the Mailman package, and the usability is greatly impaired by the fact that
dmarc wrapping, which we rely on, is deleting CC entries.

This has been fixed in
https://gitlab.com/mailman/mailman/-/merge_requests/891

Would it be possible to backport?

-- System Information:
Debian Release: 11.0
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.10.0-8-amd64 (SMP w/2 CPU threads)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages mailman3 depends on:
pn  dbconfig-sqlite3 | dbconfig-pgsql | dbconfig-mysql | dbconfi  <none>
ii  debconf [debconf-2.0]                                         1.5.77
ii  init-system-helpers                                           1.60
ii  logrotate                                                     3.18.0-2
ii  lsb-base                                                      11.1.0
ii  python3                                                       3.9.2-3
pn  python3-aiosmtpd                                              <none>
pn  python3-alembic                                               <none>
pn  python3-authheaders                                           <none>
pn  python3-authres                                               <none>
pn  python3-click                                                 <none>
ii  python3-dateutil                                              2.8.1-6
pn  python3-dnspython                                             <none>
pn  python3-falcon                                                <none>
pn  python3-flufl.bounce                                          <none>
pn  python3-flufl.i18n                                            <none>
pn  python3-flufl.lock                                            <none>
pn  python3-gunicorn                                              <none>
pn  python3-importlib-resources                                   <none>
pn  python3-lazr.config                                           <none>
ii  python3-passlib                                               1.7.4-1
ii  python3-psycopg2                                              2.8.6-2
pn  python3-public                                                <none>
ii  python3-requests                                              2.25.1+dfsg-2
pn  python3-sqlalchemy                                            <none>
pn  python3-zope.component                                        <none>
pn  python3-zope.configuration                                    <none>
pn  python3-zope.event                                            <none>
pn  python3-zope.interface                                        <none>
ii  ucf                                                           3.0043

Versions of packages mailman3 recommends:
pn  default-mta | mail-transport-agent  <none>

Versions of packages mailman3 suggests:
pn  lynx | www-browser  <none>
pn  mailman3-doc        <none>
ii  postgresql          13+225