<thead> <tr>{1,unbounded}</tr> </thead>
<tbody> <tr>{1,unbounded}</tr> </tbody>
<tfoot> <tr>{1,unbounded}</tr> </tfoot>
This attribute is used to identify content that is intended for a particular audience.
For use in notifying downstream publishing channels if there is content that is specific for their channel.
This attribute represents a graduated range of values forming a standard system for measuring or grading the element that it is assigned to.