Comment 4 for bug 1948482

update-manager reading /usr/share/ubuntu-release-upgrader/deb2snap.json was implemented in https://code.launchpad.net/~marcustomlinson/update-manager/update-manager/+merge/380060.

The rationale is that if a deb was replaced by a snap in the seeds, then users updating will also want to transition. It makes sense, but it contradicts the statement in https://discourse.ubuntu.com/t/feature-freeze-exception-seeding-the-official-firefox-snap-in-ubuntu-desktop/24210 that « This will only impact users of Ubuntu Desktop installing 21.10 or upgrading to 21.10. If you run one of the flavours, you won’t be affected - yet. ».