I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written primarily for the benefit of the security area directors. Document editors and WG chairs should treat these comments just like any other last call comments. Summary: I do not think that it is ready (see below), but presumably there is some backstory that I'm not aware of, or it wouldn't be here. I don't see any *security* issues, but the document is very unclear. It *looks* like it just tries to add "+json-seq" to the IANA Structured Syntax Suffix Registry, but I don't see why it is Standards Track, or why it need to be an RFC at all; the registry is Expert Review, and RFC 6838 Section 6 seems clear. Other issues: It does not contain a Security Considerations section, and there are a number of broken references (e.g: it says: "Online access to all versions and files is available on github [2]." - but [2] is a link to: http://www.rfc-editor.org/info/rfc6838) It is a -00, submitted Sept 23rd 2016, and the document on which it was based (draft-json-seq-suffix-00) was also a -00, submitted Sept 19th 2016. The only changes between the 2 are the metadata (name, date). There has been basically no discussion (at least, that I can find), closest is: https://mailarchive.ietf.org/arch/search/?email_list=art&index=AxC0J7zxKU_wH1jOrkZ0ZZUUcs4 ? I *think* that it is simply trying to add "+json-seq" to the IANA Structured Syntax Suffix Registry ( http://www.iana.org/assignments/media-type-structured-suffix/media-type-structured-suffix.xhtml) -- unfortunately it does this very poorly. It starts off by saying (note tense): "IANA has added the following "+json-seq" structured syntax suffix to its registry of structured syntax suffixes established by [2]". [2] references to RFC 6838 - "Media Type Registration", which creates a number of registries - while looking I found " http://www.iana.org/assignments/media-types/media-types.xhtml", which does indeed have "json-seq". Because of the "IANA has added" I assumed that this was what was being referenced. The IANA considerations section needs work... Nits: Section 1: how a media type can signal that it is based on another media type as [O] way of how a media type can signal [P] way for a media type to signal [R] readability; original was a bit awkward Section 3: Applications encountering such a media type then can either simply [O] then can either [P] can then either [R] readability W