Documentation for nm-settings-keyfile references nm-settings(5) manpage which does not exist.
It appears that nm-settings(5) used to exist but was merged into nm-settings-cli(5) (is this true?) Regardless, the information desired is in nm-settings-cli(5) and now nm-settings(5) is a symlink to it. The documentation in nm-settings-keyfile(5) should be updated to reflect this reality. This should ideally also convert the nm-settings(5) references in the web documentation to links as well. This should be done for references in nm-settings-ifcfg-rh(5) and any other locations in the documentation.