[media-types] [IANA #1443379] Registration of MIME media type application/vnd.phbk+xml

Hi Darrel,

Can you review this revised request (just sec cons and change controller)? Their updated form comes immediately after these answers. They've told us that the new change controller name is their own full name. 

thanks,
Amanda

===

> 1.
> Why is charset a required parameter here?  The application/xml
> mediatype does not require this parameter, why would this +xml media
> type?

While application/xml doesn't require charset, many +xml subtypes (like application/svg+xml) explicitly require it to ensure UTF-8 is handled consistently across implementations. Requiring it here guarantees predictable behavior on mobile and desktop platforms.

> 2.
> It would be good to reference the XML security considerations
> https://www.rfc-editor.org/rfc/rfc7303#section-10

I've added the reference to RFC 7303, Section 10 as requested.

> 3.
> The author change controller should be an actual name and include
> contact information.

Please update to: Lost Idea Experiments ([email protected])

===

Type name: application

Subtype name: vnd.phbk+xml

Required parameters: charset (Encoding: UTF-8)

Optional parameters: N/A

Encoding considerations: 8bit

Since this is a text-based XML format, 8bit encoding is sufficient for transporting contact data like names and addresses.

Security considerations: The .phbk format is a non-executable, text-based XML structure used for storing contact information such as phone numbers, emails, and physical addresses. It does not contain active content, scripts, or macros. There is no risk of code execution on the host machine. Implementers should follow the security considerations outlined in RFC 7303, Section 10 (https://www.rfc-editor.org/rfc/rfc7303#section-10), particularly regarding external entity expansion and recursive processing.

Interoperability considerations: This format is designed to be parsed by any XML-compliant software. It has been tested on mobile platforms (Android) and desktop systems to ensure consistent data rendering.

Published specification: https://github.com/afifashamsadvivo/phbk

Applications that use this media type: Custom phonebook managers and contact backup utilities.

Fragment Identifier Considerations: The .phbk file type does not use or require fragment identifiers. It is intended for custom configurations and data storage in AI-based systems, not for referencing specific document fragments.

Restrictions on Usage: The .phbk file type is primarily intended for use in technical environments related to AI projects. It is not designed for general public use or non-technical applications.

Additional information:

Deprecated Alias Names: There are no deprecated alias names for the .phbk file type.
Magic number(s): None. Identification is based on the .phbk file extension or the <phonebook> root element.
File extension(s): .phbk
Macintosh file type code(s): TEXT

Person & email address to contact for further information:

afifashamsadvivo - [email protected]

Intended usage: COMMON

Author/Change controller: Lost Idea Experiments ([email protected])

> 
> Darrel
> 
> ________________________________
> From: Darrel Miller <[email protected]>
> Sent: Saturday, February 21, 2026 1:04 PM
> To: [email protected] <[email protected]>
> Cc: [email protected] <[email protected]>; Darrel Miller
> <[email protected]>
> Subject: Re: [IANA #1443379] Registration of MIME media type
> application/vnd.phbk+xml
> 
> This registration is ok.  It would be better if the URL to the
> specification actually pointed to a specification rather than a git
> repo with a single example.  But specifications are not a MUST for vnd
> tree, so we can proceed.
> 
> Darrel
> ________________________________
> From: Amanda Baber via RT <[email protected]>
> Sent: Friday, February 20, 2026 9:25 PM
> Cc: [email protected] <[email protected]>; Darrel Miller
> <[email protected]>
> Subject: [IANA #1443379] Registration of MIME media type
> application/vnd.phbk+xml
> 
> Hi Darrel,
> 
> Sending a reminder for this request from February 6th.
> 
> thanks,
> Amanda
> 
> On Sat Feb 07 04:36:18 2026, amanda.baber wrote:
> > Hi Darrel,
> >
> > Could you review this one for us by February 20th?
> >
> > This was initially based on an older version of the registration
> > template, so you might want to check that we've captured all of the
> > fields.
> >
> > thanks,
> > Amanda
> >
> > =====
> >
> > Type name: application
> >
> > Subtype name: vnd.phbk+xml
> >
> > Required parameters: charset (Encoding: UTF-8)
> >
> > Optional parameters: N/A
> >
> > Encoding considerations: 8bit
> >
> > Since this is a text-based XML format, 8bit encoding is sufficient
> > for
> > transporting contact data like names and addresses.
> >
> > Security considerations: The .phbk format is a non-executable, text-
> > based XML structure used for storing contact information such as
> > phone
> > numbers, emails, and physical addresses. It does not contain active
> > content, scripts, or macros. There is no risk of code execution on
> > the
> > host machine.
> >
> > Interoperability considerations: This format is designed to be parsed
> > by any XML-compliant software. It has been tested on mobile platforms
> > (Android) and desktop systems to ensure consistent data rendering.
> >
> > Published specification: https://github.com/afifashamsadvivo/phbk
> >
> > Applications that use this media type: Custom phonebook managers and
> > contact backup utilities.
> >
> > Fragment Identifier Considerations: The .phbk file type does not use
> > or require fragment identifiers. It is intended for custom
> > configurations and data storage in AI-based systems, not for
> > referencing specific document fragments.
> >
> > Restrictions on Usage: The .phbk file type is primarily intended for
> > use in technical environments related to AI projects. It is not
> > designed for general public use or non-technical applications.
> >
> > Additional information:
> >
> > Deprecated Alias Names: There are no deprecated alias names for the
> > .phbk file type.
> >   Magic number(s): None. Identification is based on the .phbk file
> > extension or the <phonebook> root element.
> > File extension(s): .phbk
> > Macintosh file type code(s): TEXT
> >
> > Person & email address to contact for further information:
> >
> > afifashamsadvivo - [email protected]
> >
> > Intended usage: COMMON
> >
> > Author/Change controller: afifashamsadvivo

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