class AppKernel extends Kernel
{
    public function registerBundles()
    {
        $bundles = [
            ...
            new CMSCoreBundleCMSCoreBundle(),
        ];

cms_core:
    resource: "@CMSCoreBundle/Resources/config/routing.yml"
    prefix:   /

cms_core_homepage:
    path:     /
    defaults: { _controller: CMSCoreBundle:Default:index }

{% extends "@CMSCoreBundle/template.html.twig" %}

{% block content %}
test
{% endblock %}

{% block content %}
Template block
{% endblock %}