The system did not have an xorg.conf file, and it had to be created manually.
Just like how the system did not have a proper sources.list I suppose.
I investigated this after Nvidia settings told me to run the nvidia-xconfig command, which — of course — also did not exist. A pattern is emerging.
Update
I've since learned that the nvidia-xconfig command is available, but in its own package (with the same name) which is not specified as a dependency or even a recommendation of the Nvidia Settings package that explicitly tells you to "just run" the command (!)