File: vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/Resources/config/request.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">

    <parameters>
        <parameter key="request.add_request_formats_listener.class">Symfony\Component\HttpKernel\EventListener\AddRequestFormatsListener</parameter>
    </parameters>

    <services>
        <service id="request.add_request_formats_listener" class="%request.add_request_formats_listener.class%">
            <tag name="kernel.event_subscriber" />
            <argument/>
        </service>
    </services>
</container>