%thead.element; Table Header Element Control For a Table
This parameter entity holds the INCLUDE or IGNORE keyword to control a conditional marked section, that determines whether the <thead> element is defined.
The NISO JATS table model parameter entity is used in the same way as the equivalent parameter entity in the XHTML 1.1 table model. Since this parameter entity was named in the same way as the XHTML 1.1 Tag Set equivalent, 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 % thead.element "INCLUDE" >