This mode is used for processing MathML embedded into Mallard documents. For most types of MathML content, it simply copies the input directly, except it outputs the MathML in a way that allows the namespace to stripped for non-XML output. It checks for Mallard linking using the mal:xref attribute and transforms this to a MathML href attribute. It also converts xlink:href attributes from MathML 2 to href attributes for MathML 3.