/etc/sudoers had been deleted, and I wanted to restore the default file from the package. I tried:
apt-get install sudo
apt-get install --reinstall sudo
apt-get remove sudo && apt-get install sudo
None of which worked but all of which warned about /etc/sudoers not existing.
In the end I did
apt download sudo && ar xv sudo && tar xf data.tar.xz ./etc/sudoers and just copied that file to /etc/sudoers, but was there a more straightforward way to restore the file?