domain-elytron.xml, missing singelton subsystem, different ejb cache type

When I compare domain-elytron.xml to domain.xml,

1) There is missing org.wildfly.extension.clustering.singleton extension installed.

2) There is changed ejb cache configuration
1254c1129
< <stateful default-access-timeout="5000" cache-ref="simple" passivation-disabled-cache-ref="simple"/>
—
> <stateful default-access-timeout="5000" cache-ref="distributable" passivation-disabled-cache-ref="simple"/>