Servlet 4 web.xml schema: listener not found

Question

Servlet 4 web.xml schema: listener not found.

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
                      http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
                version="4.0">
 ....
</web-app>

The schema at http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd is not a complete schema. Trying to look for listener element.