How to delete a locked app using superuser privileges?

Read the shell script:

/Library/Application Support/org.pqrs/Karabiner-Elements/uninstall_core.sh

or

• https://github.com/pqrs-org/Karabiner-Elements/blob/master/src/scripts/uninstall_core.sh

In summary:

• Unload the kernel extensions.
• Clear immutable flags nouchg,noschg from the apps.
• Remove the files from /Library and /Applications. Remember we used sudo with the script.
• Refresh kernel extension cache: kextcache.
• https://github.com/pqrs-org/Karabiner-Elements/blob/master/src/scripts/uninstall.sh
• Kill all orphan/ background processes if any.
• Prompt you to restart the computer.