Quote the relevant commit message:
settings: ensure that "plugins-=ifcfg-rh" works with the default plugins
On Fedora/RHEL, the default for main.plugins is "ifcfg-rh". You would
expect that a single configuration file
[main]
plugins-=ifcfg-rh
would result in an empty list of plugins (which subsequently gets
completed with "keyfile").
That didn't happen due to a bug. Fix it.