<idea-plugin>
  <id>com.intellij.myPlugin</id>

  <extensionPoints>
    <extensionPoint name="myExt" beanClass="MyExtBean"/>
  </extensionPoints>

  <extensions defaultExtensionNs="com.intellij.myPlugin">
    <myExt <warning descr="Deprecated attribute 'old'">old="java.lang.Runnable"</warning> attr="value"/>
  </extensions>

</idea-plugin>