External module for one of the MathML Tag Sets, either: the Mathematical Markup Language (MathML) 2.0 Tag Set or the Mathematical Markup Language (MathML) 3.0 Tag Set. This module is named in the Module to Name the Modules (%modules.ent;) and then called from one of the MathML setup modules (%mathmlsetup.ent; or %mathml3-mathmlsetup.ent;) to include MathML 2.0 or MathML 3.0 elements in this Tag Set.