Missing DTD file in module

I noticed that XML file generated by module contains this part:

<?xml version="1.0" standalone="no"?>
<!DOCTYPE taxonomy SYSTEM "taxonomy.dtd">

First of all root item is vocabulary and not taxonomy and second taxonomy.dtd file is missing. What I propose is to change DOCTYPE to look like this:

<!DOCTYPE vocabulary [
<!ELEMENT vocabulary ( vid?        ,
name?       ,
description?,
help?       ,
relations?  ,
hierarchy?  ,
multiple?   ,
required?   ,
tags?       ,
module?     ,
weight?     ,
nodes?      ,
term*
) >
<!ELEMENT vid         (#PCDATA)>
<!ELEMENT name        (#PCDATA)>
<!ELEMENT description (#PCDATA)>
<!ELEMENT help        (#PCDATA)>
<!ELEMENT relations   (#PCDATA)>
<!ELEMENT hierarchy   (#PCDATA)>
<!ELEMENT multiple    (#PCDATA)>
<!ELEMENT required    (#PCDATA)>
<!ELEMENT weight      (#PCDATA)>
<!ELEMENT module      (#PCDATA)>
<!ELEMENT nodes       (#PCDATA)>
<!ELEMENT tags        (#PCDATA)>
<!ELEMENT term (
tid?        ,
vid?        ,
name?       ,
description?,
weight?     ,
sortorder?  ,
depth?      ,
parent*    
)>
<!ELEMENT tid         (#PCDATA)>
<!ELEMENT sortorder   (#PCDATA)>
<!ELEMENT depth       (#PCDATA)>
<!ELEMENT parent      (#PCDATA)>
]>

This is a complete DTD embedded in header so that validation can be done without any external file present or not.

I also supply taxonomy.dtd just in case.