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.
YAML::PP::LibYAML is a subclass of YAML::PP. Instead of using YAML::PP::Parser as a the backend parser, it uses YAML::PP::LibYAML::Parser which calls YAML::LibYAML::API, an XS wrapper around the C libyaml.