symfony/src/Symfony/Bundle/FrameworkBundle/Resources/config/assets.xml

<?xml version="1.0" ?>

<container xmlns="http://symfony.com/schema/dic/services"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>

        <service id="assets.packages" class="Symfony\Component\Asset\Packages">
            <argument type="service" id="assets.empty_package" /> <!-- default package -->
            <argument type="collection" /> <!-- named packages -->
        </service>

        <service id="assets.empty_package" class="Symfony\Component\Asset\Package" public="false">
            <argument type="service" id="assets.empty_version_strategy" />
        </service>

        <service id="assets.context" class="Symfony\Component\Asset\Context\RequestStackContext">
            <argument type="service" id="request_stack" />
        </service>

        <service id="assets.path_package" class="Symfony\Component\Asset\PathPackage" abstract="true">
            <argument /> <!-- base path -->
            <argument type="service" /> <!-- version strategy -->
            <argument type="service" id="assets.context" />
        </service>

        <service id="assets.url_package" class="Symfony\Component\Asset\UrlPackage" abstract="true">
            <argument /> <!-- base URLs -->
            <argument type="service" /> <!-- version strategy -->
            <argument type="service" id="assets.context" />
        </service>

        <service id="assets.static_version_strategy" class="Symfony\Component\Asset\VersionStrategy\StaticVersionStrategy" abstract="true">
            <argument /> <!-- version -->
            <argument /> <!-- format -->
        </service>

        <service id="assets.empty_version_strategy" class="Symfony\Component\Asset\VersionStrategy\EmptyVersionStrategy" public="false" />

        <service id="assets.preload_manager" class="Symfony\Component\Asset\Preload\PreloadManager" public="false" />

        <service id="asset.preload_listener" class="Symfony\Component\Asset\EventListener\PreloadListener">
            <argument type="service" id="assets.preload_manager" />

            <tag name="kernel.event_subscriber" />
        </service>

    </services>
</container>