Implementer-Friendly Specification of Message and MIME-Part Header Fields and Field Components

Implementation of generators and parsers of header fields requires certain information about those fields. Interoperability is most likely when all such information is explicitly provided by the technical specification of the fields. Lacking such explicit information, implementers may guess, and interoperability may suffer. This memo identifies information useful to implementers of header field generators and parsers. This memo provides information for the Internet community.