The current format of the Subject line mailed by unattended-upgrades:

unattended-upgrades result for hostname.domain: SUCCESS

It would be desirable to add the content of /etc/debian_chroot, if it exists e.g.:

unattended-upgrades result for hostname.domain (stable chroot i386): SUCCESS

...similar to what the Bourne shell prompt does.

Thanks!

- -- System Information:
Debian Release: bookworm/sid
  APT prefers unstable
  APT policy: (900, 'unstable')
Architecture: i386 (x86_64)

Kernel: Linux 5.10.0-8-amd64 (SMP w/8 CPU threads)
Locale: LANG=fi_FI.UTF-8, LC_CTYPE=fi_FI.UTF-8 (charmap=UTF-8), LANGUAGE=fi:en
Shell: /bin/sh linked to /bin/dash
Init: unable to detect

Versions of packages unattended-upgrades depends on:
ii  debconf [debconf-2.0]  1.5.77
ii  lsb-base               11.1.0
ii  lsb-release            11.1.0
ii  python3                3.9.2-3
ii  python3-apt            2.2.1
ii  python3-dbus           1.2.18-3
ii  python3-distro-info    1.0
ii  ucf                    3.0043
ii  xz-utils               5.2.5-2

Versions of packages unattended-upgrades recommends:
ii  systemd-cron [cron-daemon]  1.5.17-3
ii  systemd-sysv                247.9-1

Versions of packages unattended-upgrades suggests:
ii  bsd-mailx                          8.1.2-0.20180807cvs-2
ii  needrestart                        3.5-4
ii  nullmailer [mail-transport-agent]  1:2.2-3
ii  powermgmt-base                     1.36
ii  python3-gi                         3.40.1-2

- -- debconf information:
* unattended-upgrades/enable_auto_updates: true
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