Prevents any DNF operation that would result in a removal of one of the protected packages from the system. These are typically packages essential for proper system boot and basic operation.
Deciding whether a package is protected is based on the package name. The set of packages names considered protected is loaded from configuration files under:
/etc/dnf/protected.d
/etc/yum/protected.d
Every line in all *.conf files there is taken as a protected package name. Moreover, the currently booted kernel package is always protected.
Complete disabling of the protected packages feature is done by disabling the plugin:
dnf --disableplugin=protected_packages erase dnf