Why does karaf start jaas boot when it's in the boot classpath?

[David Jencks]

The jaas boot code only works if its loaded in the system classloader, and it 
is there, so why is this in startup.properties?

org/apache/felix/karaf/jaas/org.apache.felix.karaf.jaas.boot/${felix.karaf.version}/org.apache.felix.karaf.jaas.boot-${felix.karaf.version}.jar=30

thanks
david jencks