<x> in <tp:nomenclature> causes validity error #76
Description
using libxml and xmllint, the <x> element in <tp:nomenclature> causes error:
xmllint: using libxml version 20904
validity error : Content model of nomenclature is not determinist: (sec-meta? , label? , tp:taxon-name , x? , tp:taxon-authority? , x? , tp:taxon-status? , x? , tp:taxon-identifier* , xref* , x? , tp:nomenclature-citation-list* , x? , (tp:type-genus | tp:type-species)? , x? , tp:taxon-type-location? , x?)