这就是我在XSD中看到的。角色只是简单的xs:string，主要用于文档。

<xs:element name="roles" minOccurs="0">
  <xs:annotation>
    <xs:documentation source="version">3.0.0+</xs:documentation>
    <xs:documentation source="description">
        The roles the contributor plays in the project. Each role is described by a <code>role</code> element, the body of which is a role name. This can also be used to describe the contribution.
    </xs:documentation>
  </xs:annotation>
  <xs:complexType>
    <xs:sequence>
      <xs:element name="role" minOccurs="0" maxOccurs="unbounded" type="xs:string"/>
    </xs:sequence>
  </xs:complexType>
</xs:element>