I don't remember how I installed the Pop_OS theme on my Ubuntu, but I want to get rid of it as when I restarted my laptop after installing this it's causing malfunctioning. My settings won't open, but somehow I figured typing this command solves it, but...
gsettings set org.gnome.ControlCenter last-panel ''
After the Settings menu opens up, whenever I click on the Display settings the settings GUI stops working and I have to run that command again.
UPDATE-: I did what was mentioned in System settings won't open on Ubuntu 20.04 LTS after adding System76/pop PPA
and now my settings menu is not visible as gnome-control-center is uninstalled and now when I try to install it output this..
As mentioned by @technastic_tc in comments the output of the following command
grep -r --include '*.list' '^deb ' /etc/apt/sources.list/etc/apt/sources.list.d/
is this
/etc/apt/sources.list:deb http://in.archive.ubuntu.com/ubuntu/ focal main restricted
/etc/apt/sources.list:deb http://in.archive.ubuntu.com/ubuntu/ focal-updates main restricted
/etc/apt/sources.list:deb http://in.archive.ubuntu.com/ubuntu/ focal universe
/etc/apt/sources.list:deb http://in.archive.ubuntu.com/ubuntu/ focal-updates universe
/etc/apt/sources.list:deb http://in.archive.ubuntu.com/ubuntu/ focal multiverse
/etc/apt/sources.list:deb http://in.archive.ubuntu.com/ubuntu/ focal-updates multiverse
/etc/apt/sources.list:deb http://in.archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
/etc/apt/sources.list:deb http://security.ubuntu.com/ubuntu focal-security main restricted
/etc/apt/sources.list:deb http://security.ubuntu.com/ubuntu focal-security universe
/etc/apt/sources.list:deb http://security.ubuntu.com/ubuntu focal-security multiverse
/etc/apt/sources.list:deb https://cloud.r-project.org/bin/linux/ubuntu focal-cran40/
/etc/apt/sources.list:deb https://dl.winehq.org/wine-builds/ubuntu/ focal main
/etc/apt/sources.list.d/micahflee-ubuntu-ppa-focal.list:deb http://ppa.launchpad.net/micahflee/ppa/ubuntu focal main
/etc/apt/sources.list.d/dawidd0811-ubuntu-neofetch-focal.list:deb http://ppa.launchpad.net/dawidd0811/neofetch/ubuntu focal main
/etc/apt/sources.list.d/git-core-ubuntu-ppa-focal.list:deb http://ppa.launchpad.net/git-core/ppa/ubuntu focal main
/etc/apt/sources.list.d/google-chrome.list:deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main
/etc/apt/sources.list.d/deadsnakes-ubuntu-ppa-focal.list:deb http://ppa.launchpad.net/deadsnakes/ppa/ubuntu focal main
/etc/apt/sources.list.d/nodesource.list:deb https://deb.nodesource.com/node_14.x focal main
/etc/apt/sources.list.d/ubuntu-desktop-ubuntu-ppa-focal.list:deb http://ppa.launchpad.net/ubuntu-desktop/ppa/ubuntu focal main
/etc/apt/sources.list.d/lutris-team-ubuntu-lutris-focal.list:deb http://ppa.launchpad.net/lutris-team/lutris/ubuntu focal main
/etc/apt/sources.list.d/vscode.list:deb [arch=amd64] http://packages.microsoft.com/repos/vscode stable main
/etc/apt/sources.list.d/steam.list:deb [arch=amd64,i386] https://repo.steampowered.com/steam/ stable steam
/etc/apt/sources.list.d/snwh-ubuntu-ppa-focal.list:deb http://ppa.launchpad.net/snwh/ppa/ubuntu focal main
/etc/apt/sources.list.d/gns3-ubuntu-ppa-focal.list:deb http://ppa.launchpad.net/gns3/ppa/ubuntu focal main
gsettings get org.gnome.desktop.interface gtk-themein your question (use the [edit] feature). – Random Person Oct 14 '20 at 15:36grep -r --include '*.list' '^deb ' /etc/apt/sources.list /etc/apt/sources.list.d/in the question. I request you to paste the full output in question (not in the comments). – Random Person Oct 15 '20 at 07:39