What settings does the Ubuntu upgrade tool change during the upgrade from 21.10 to 22.04?

I am talking about this upgrade tool: http://archive.ubuntu.com/ubuntu/dists/jammy/main/dist-upgrader-all/current/jammy.tar.gz which I am sure the do-release-upgrade uses to upgrade to 22.04 from 21.10. I found it in https://changelogs.ubuntu.com/meta-release.

During the upgrade, what I have observed is:

1. Updates sources.list.
2. Disables third-party repositories to avoid errors with them (can be enabled again after the upgrade).
3. Runs apt update
4. Upgrades all the packages using apt: upgrade and dist-upgrade
5. Has a list called demoted.cfg (which is a list of packages that are not needed to the newer Ubuntu version and are meant to be deleted if they aren't automatically installed, etc.). Gets the packages in the list, checks which of them are manually installed, and combines them to the list of apt autoremove, and removes all of them after asking you.
6. Also removes the Firefox that was installed using apt. Or more clearly: it removes packages listed in dep2snap.cfg (and installs the snap version?). Somewhere around these steps.
7. Reboots the system

Are there any other steps here that I am missing? I need to know as I need to revert any unexpected changes to the system.
Example: Changes to the system that helps the system to be stable during the upgrade. But aren't needed after the upgrade.

Note: All the .cfg files mentioned above are in the upgrade tool that do-release-upgrade uses. Which I have listed above.