After testing the Pop theme via their PPA, I made a distribution upgrade from Focal Fossa to Pop!_OS by mistake. I did not realize that installing the System76 PPA meant that the system would try to "upgrade" from Ubuntu to Pop!_OS...
Is there a way to get back to Ubuntu Focal Fossa without re-installing the OS?
The file /etc/apt/sources.list looks "normal":
deb focal universe restricted multiverse main
deb focal-security restricted universe multiverse main
deb focal-updates restricted universe multiverse main
deb focal-backports restricted universe multiverse mainBut there is another file in /etc/apt/preferences.d called pop-default-settings which explicitly references pop:
Package: *
Pin: release o=LP-PPA-system76-pop
Pin-Priority: 1001
Package: *
Pin: release o=LP-PPA-system76-proposed
Pin-Priority: 10011 Answer
Install the ppa-purge tool. It removes a package and reverts back to original packages. The pop-default-settingsfile in /etc/apt/preferences.d is a left over that does not have any function anymore because the PPA to which the preference applies is gone.
