(registered 2023-05-02, last updated 2023-05-02)

Media type name: application

Media subtype name: prs.implied-structure

Required parameters: 

   signature: A non-empty case-sensitive sequence of arbitrary ASCII 
      characters located at "offset" in the file.

Optional parameters: 

   offset: A decimal-encoded integer that specifies where the 
      "signature" appears in the file. If not present, it MUST be 
      treated as 0. Negative values identify offsets from the end of 
      the file, such as -1 for the position of the last byte, -2 for 
      second to last, and so forth.

Encoding considerations: binary

Security considerations: The content of the media type is completely 
   arbitrary with the exception of the presence of "signature" at 
   "offset". Therefore, any such file may contain executable or 
   active content or code, and the file itself may be executable if 
   "signature" is a sequence commonly used for executable files. When 
   processing this type, applications MUST ensure that the structure 
   of the file matches "signature" and "offset", and if they intend 
   to assign a more concrete media type to the file, they SHOULD 
   verify that it is valid. Applications MUST NOT open files coming 
   from untrusted sources if it could lead to arbitrary code 
   execution.

Interoperability considerations: Applications that accept or produce 
   this type should not be assumed to have knowledge of more than the 
   signature. It is not guaranteed that an application offering this 
   type will produce a file in a format that is most commonly 
   associated with the signature, and it is not guaranteed that an 
   application accepting this type will be able to process it any of 
   the formats associated with the signature.

Published specification: N/A

Applications which use this media: This media type is intended for 
   applications that have to guess the media type of a file, but do 
   not contain heuristics that allow to pick a more concrete media 
   type with acceptable confidence.

Fragment identifier considerations: N/A

Restrictions on usage: N/A

Additional information:

   1. Deprecated alias names for this type: N/A
   2. Magic number(s): As indicated by "signature"
   3. File extension(s): N/A
   4. Macintosh file type code: N/A
   5. Object Identifiers: N/A

General Comments: This media type identifies a meta-format that 
   encompasses all formats which require "signature" at "offset". It 
   it intended for use in applications that describe files using 
   media types, but do not have sufficient heuristics to output a 
   more specific media type. In such a case, an arbitrary number of 
   printable ASCII characters can be taken from the beginning of the 
   file and stored in the "signature" parameter.

   Examples:

   application/prs.implied-structure;signature=GIF87a - Any file 
   starting with "GIF87a", such the 1987 version of GIF.

   application/prs.implied-structure;signature=ID3;offset=-128 - Any 
   file having "ID3" at position 128 from the end, such as files 
   storing ID3v1 metadata.

Person to contact for further information:

   1. Name: Marek Čermák
   2. Email: cermmarek&gmail.com

Intended usage: LIMITED USE

   It is not recommended to use this media type when a more concrete 
   type is known. Its use beyond automated archival, content 
   negotiation and other purposes in general file hosting is limited. 
   Applications should not advocate themselves as accepting this 
   media type if they require more specific structure or format.

Author/Change controller: Marek Čermák <cermmarek&gmail.com>