Bug#1020852: cinnamon: Removing Thunderbird deletes all Cinnamon-related packages

[Green <usergreen@users.sourceforge.net>]

Source: cinnamon
Version: 4.8.6-2+deb11u1
Severity: important

Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?
        Users can NOT delete Thunderbird mailer, even if they do not want to
use and installing thunderbird takes a lot of hard disk space.
   * What exactly did you do (or not do) that was effective (or
     ineffective)?
         I was going to delete thunderbird.
   * What was the outcome of this action?
           The above-mentioned package have a dependency to Thunderbird mailer
when a fresh installation.

But it seems that everyone does not need Thunderbird mailer, which takes large
disk space. If someone is attempting to remove Thunderbird, Cinnamon desktop
itself are automatically going to removed due to the dependency. I think this
behavior is not good for many users.
   * What outcome did you expect instead?
Thunderbird should NOT automatically installed by "apt install cinnamon" or,
removing thunderbird did not have dependency on cinnamon.



-- System Information:
Debian Release: 10.13
  APT prefers oldstable-updates
  APT policy: (500, 'oldstable-updates'), (500, 'oldstable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-21-amd64 (SMP w/2 CPU cores)
Locale: LANG=ja_JP.UTF-8, LC_CTYPE=ja_JP.UTF-8 (charmap=UTF-8), LANGUAGE=ja_JP.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled