DSD 2.0 description of XHTML1.0-Transitional This description differs from the DTD version in the following ways, as annotated with meta attributes from the namespace http://www.brics.dk/DSD/2.0/meta: This description captures some requirements that only appear as comments in the DTD. These extensions are marked by "non-DTD" attributes. All input field attribute declarations are marked with "input-field". Elements and attributes that are deprecated in the XHTML 1.0 / HTML 4.01 specification are marked by "deprecated" attributes. IDREFS cannot be expressed - these are marked with "idrefs".