Attributes commonly used throughout the XHTML Table Model Tag Set, as modified, to denote 1) whether an alternate form of a table is present and 2) the subject or content type for preservation of semantic integrity
See W3C documentation for the XHTML table model.
Since this is parameter entity is defined in the public XHTML Tag Set, it does not follow the naming conventions for this Tag Set: it is in mixed not lower case and the separator character is a period not a hyphen.
<!ENTITY % Common.attrib "id ID #IMPLIED content-type CDATA #IMPLIED %Core.extra.attrib;" >
id ID #IMPLIED content-type CDATA #IMPLIED style CDATA #IMPLIED