Bind and Bvar

In the human-readable version of MathML3, bvar allows CommonAtt for both
Strict Content and Full Content, ... but in the DTD and RNC versions, the
bvar element does not allow any attributes.

My question is which is wrong? the DTD/RNC? or the text? I would like to be
able to use id and class on bvar, but my documents will not validate if I
do.

Regards,
Andrew Robbins