I think this is more a matter of misunderstanding the fact that ISO 8601 is a larger and more complicated spec than people think.  You'll note that the original complaint also seems to think that a timezone is required (it is not). You can find a copy of RFC 3339 here: https://tools.ietf.org/html/rfc3339

Which states:


      NOTE: ISO 8601 defines date and time separated by "T".
      Applications using this syntax may choose, for the sake of
      readability, to specify a full-date and full-time separated by
      (say) a space character.

I think this is sufficient to refer to this as an RFC 3339 datetime, as a spec-compliant parser should be able to handle it just fine. Then there is no need for "x-like" anywhere in the documentation, which is just confusing. I do agree that the precise spec should be given.