I tested an upgrade of an Ubuntu 18.04 system with xubuntu-desktop installed and gnome-software-plugin-snap remained installed.
bdmurray@xubuntu-bionic-server-amd64:/tmp/uru$ grep "upgrader version" /var/log/dist-upgrade/main.log 2020-09-21 13:08:57,559 INFO release-upgrader version '20.04.27' started bdmurray@xubuntu-bionic-server-amd64:/tmp/uru$ apt-cache policy xubuntu-desktop xubuntu-desktop: Installed: 2.233 Candidate: 2.233 Version table: *** 2.233 500 500 http://192.168.10.7/ubuntu focal/universe amd64 Packages 100 /var/lib/dpkg/status bdmurray@xubuntu-bionic-server-amd64:/tmp/uru$ apt-cache policy gnome-software-plugin-snap gnome-software-plugin-snap: Installed: 3.36.1-0ubuntu0.20.04.0 Candidate: 3.36.1-0ubuntu0.20.04.0 Version table: *** 3.36.1-0ubuntu0.20.04.0 500 500 http://192.168.10.7/ubuntu focal-updates/main amd64 Packages 100 /var/lib/dpkg/status 3.36.0-0ubuntu3 500 500 http://192.168.10.7/ubuntu focal/main amd64 Packages -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1894919 Title: gnome-software-plugin-snap consider an unwanted removal for 20.04 ubuntu-desktop To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1894919/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs