RFC 2387, "The MIME Multipart/Related Content-type", August 1998

Errata ID: 5578
Status: Verified
Type: Technical
Publication Format(s) : TEXT
Reported By: Sloane Bernstein
Date Reported: 2018-12-18
Verifier Name: Barry Leiba
Date Verified: 2020-05-05

Section .4 says:

     related-param   := [ ";" "start" "=" cid ]
                        [ ";" "start-info"  "="
                           ( cid-list / value ) ]
                        [ ";" "type"  "=" type "/" subtype ]
                        ; order independent

It should say:

     related-param   := ( ";" "type"  "=" type "/" subtype )
                        [ ";" "start" "=" cid ]
                        [ ";" "start-info"  "="
                           ( cid-list / value ) ]
                        ; order independent, "type" is required

Notes:

The "type" parameter is specified by the rest of the document to be mandatory, but the ABNF in section 3.4 indicates that it is optional. Even though the ABNF is specified somewhat informally (and arguably should be formalized if this RFC is ever re-issued), it should not be giving information that contradicts the formal part of the specification (e.g., section 2).

===== Verifier notes =====
As the reporter says, the ABNF here needs more work, and that should be held for document update. This particular item, though, does, indeed, contradict the normative text. I have also moved the required item to the top of the parameter list for clarity.

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