<macroSpec xmlns="http://www.tei-c.org/ns/1.0" rend="add" ident="data.BOOLEAN.unknown" module="MEI" type="dt"> <desc xml:lang="en">Boolean attribute values and "unknown".</desc> <content> <valList type="closed"> <valItem ident="true"> <desc xml:lang="en">True.</desc> </valItem> <valItem ident="false"> <desc xml:lang="en">False.</desc> </valItem> <valItem ident="unknown"> <desc xml:lang="en">Unknown.</desc> </valItem> </valList> </content> </macroSpec>