Request for review of CEA Task Model Description media type: application/cea-2018+xml

[Bjoern Hoehrmann]

* Gottfried Zimmermann wrote:
>The Consumer Electronics Association (CEA) has released standard CEA-2018 on
>Task Model Descriptions (see http://www.ce.org/cea-2018.  

>Registration Request:
>
>Type name: application
>
>Subtype name: cea-2018+xml
>
>Required parameters: none
>
>Optional parameters: none
>
>   Note that (in contrast to application/xml) no charset parameter is
>defined since CEA-2018 specifies UTF-8 as the required file format.

I do not think this is a valid reason to omit the charset parameter. Do
note that including the charset parameter is a SHOULD-level requirement
of RFC 3023 for +xml types. If you truly need to omit the parameter, it
would be better to omit the +xml from the name.

The reason is that, if you actually have a `application/cea-2018+xml;
charset=example` resource a tool with no knowledge of the specific type
it would consider it to be in the `example` encoding, whereas CEA-2018
applications would probably ignore the parameter and assume UTF-8.

A better solution would be to have an optional charset parameter and
e.g. require consumers of the type to reject content that specifies the
parameter with a value indicating some other encoding than UTF-8, or
whatever is done with entites that have a non-UTF-8 BOM or XML encoding
declaration.