I executed do-release-upgrade on desktop 18.04 and then realized that this command is for servers. But it started the upgrade process anyway without any prompt, rewrote configuration files and only stopped to tell me that it had disabled some sources and asked to press [Space] to continue. I hit Ctrl+C and aborted the process.
Now if I execute update-manager, my system is in this broken state:
How can I revert it back to 18.04? I'd don't want to make this Partial Upgrade that looks like a recipe for a disaster.
UPDATE: I am running etckeeper on my system. I could inspect changes with git diff over /etc contents - you can inspect them here - https://pastebin.ubuntu.com/p/8MsjtGqBmf/ The only file that is affected is sources.list. But reverting it has no effect. Still the same window is there. I guess there may be changes to /usr or some other place.
There is What does `do-release-upgrade` really do? but I still do not see what more I can revert.
