Comment 0 for bug 1947501

Steps to reproduce:

1. Install Ubuntu MATE 21.10 online or off-line (does not really matter)
2. Login to freshly installed system
3. Run `update-manager` manually

Expected results:
* update-manager founds some useful updates and install them

Actual results:
* update-manager founds some useful updates and will remove Firefox web-browser to replace it with Snap version
See screenshot and its OCR main part:

  Details of updates
    Install or remove
        Duplicate packages to be removed
            Firefox Web Browser

Additional info:
* in /usr/share/ubuntu-release-upgrader/deb2snap.json you clearly state the dependency on ubuntu-desktop package, but flavours does not have such package installed, so it is a bug.

Workaround:
* mark Firefox as manually installed by `sudo apt-mark manual firefox` and then launch `update-manager` again.

Documented on:
* https://askubuntu.com/q/1369778
* https://ubuntu-mate.community/t/way-to-avoid-snap-version-of-firefox-and-continue-to-use-deb-package-on-freshly-installed-ubuntu-mate-21-10/24691

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: update-manager 1:21.10.4
ProcVersionSignature: Ubuntu 5.13.0-19.19-generic 5.13.14
Uname: Linux 5.13.0-19-generic x86_64
ApportVersion: 2.20.11-0ubuntu70
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: MATE
Date: Sun Oct 17 16:34:57 2021
GsettingsChanges:
 b'com.ubuntu.update-manager' b'launch-count' b'1'
 b'com.ubuntu.update-manager' b'first-run' b'false'
 b'com.ubuntu.update-manager' b'launch-time' b'int64 1634477674'
InstallationDate: Installed on 2021-10-17 (0 days ago)
InstallationMedia: Ubuntu-MATE 21.10 "Impish Indri" - Release amd64 (20211012)
PackageArchitecture: all
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)