<!-- This isn't a good idea; we should be using "ID" instead of "NMTOKEN" -->
<!-- However, "NMTOKEN" is strictest definition that is both compatible with existing -->
<!-- usage ([0-9]+) and with the "ID" type. -->
- <attribute name="id" type="NMTOKEN" />
+ <attribute name="id" use="optional" type="NMTOKEN" />
<attribute name="bytes" use="optional" type="nonNegativeInteger" />
</extension>
</simpleContent>