These two fields allow to specify a different default assignee for ticket opened against this package in bugzilla. Note: The EPEL field is always displayed for packages in the 'rpms' namespace regardless of whether it is used in bugzilla or not.
Fedora users - Nagios plugins for Fedora have all been packaged separately. For example, to install the check_http just install nagios-plugins-http. All plugins are installed in /usr/lib/nagios/plugins/