what is the purpose of including empty beans.xml in CDI implemenations projects?

what is the purpose of including empty beans.xml in CDI implemenations
projects?

I am using weld,a RI of CDI as dependency injection component in my
JSF-EJB-JPA web app. I see in my project we have empty beans.xml in
META-INF/beans.xml in ejb.jar and WEB-INF/beans.xml in my WAR. I don't get
it why we need to keep empty beans.xml when there nothing defined in that
file?