When attempting to write a (seemingly) valid jboss-deployment-structure.xml using the schema in ./docs, my document fails to validate.

This is because of the settings used in the XSD. Have these XSDs been used to validate actual documents? By setting unqualified to 'qualified' then the documents will probably validate.

$ git grep elementFormDefault..unqualified
jboss-deployment-dependencies-1_0.xsd: elementFormDefault="unqualified"
jboss-deployment-structure-1_0.xsd: elementFormDefault="unqualified"
jboss-deployment-structure-1_1.xsd: elementFormDefault="unqualified"
jboss-deployment-structure-1_2.xsd: elementFormDefault="unqualified"
jboss-ejb-client_1_0.xsd: elementFormDefault="unqualified"
jboss-ejb-client_1_1.xsd: elementFormDefault="unqualified"
jboss-ejb-client_1_2.xsd: elementFormDefault="unqualified"
jboss-jpa_1_0.xsd: elementFormDefault="unqualified"