Domains are listed in the abuse.rfc-clueless.org zone based on:
RFC 2142 (Mailbox names for common services, roles and functions, 1997) codifies the until-then de facto standard of providing abuse as a standard mailbox for reporting [i]nappropriate public behaviour of the system's users. The purpose of the mailbox is to be a known contact for users who are otherwise unfamiliar with the service, and as such alternative reporting systems are not a valid replacement.
This zone was originally populated from RFC-Ignorant.org's final data set.