<!-- see o.a.m.plugin.descriptor.Requirement -->
      <fields>
        <field>
          <name>role</name>
          <required>true</required>
          <version>1.0.0+</version>
          <type>String</type>
          <description></description>
        </field>
        <field xml.tagName="role-hint">
          <name>roleHint</name>
          <version>1.0.0+</version>
          <type>String</type>

        <field>
          <name>roles</name>
          <version>3.0.0+</version>
          <description>
            The roles the contributor plays in the project. Each role is described by a
            {@code role} element, the body of which is a role name. This can also be used to
            describe the contribution.
          </description>
          <association>
            <type>String</type>