Attributes commonly used throughout the XHTML Table Model DTD, as modified by NCBI to denote 1) whether an alternate form of a table is present and 2) the subject or content type for preservation of semantic integrity
Since this is Parameter Entity is defined in the public XHTML DTD, it does not follow the naming conventions for this DTD: it is in mixed not lower case and the separator character is a period not a hyphen.
<!ENTITY % Common.attrib "alternate-form-of IDREF #IMPLIED content-type CDATA #IMPLIED id ID #IMPLIED" >
XHTMLtablesetup.ent