You can just grap them from above and apply the changes...

````xml
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
    my-bundle="http://example.org/schema/dic/my_bundle">

    <my-bundle:config logging="true" />
    <!-- true, as expected -->

     <my-bundle:config logging="%kernel.debug%" />
     <!-- true/false (depends on 2nd parameter of AppKernel),
           as expected, because %kernel.debug% inside configuration
           gets evaluated before being passed to the extension -->

    <my-bundle:config />
    <!-- passes the string "%kernel.debug%".
         Which is always considered as true.
         The Configurator does not know anything about
         "%kernel.debug%" being a parameter. -->
</container>
````