18 files declare their use of EventDispatcher in Zircon Profile 8.0

AbstractEventDispatcherTest.php in vendor/symfony/event-dispatcher/Tests/AbstractEventDispatcherTest.php

ApplicationTest.php in vendor/symfony/console/Tests/ApplicationTest.php

ContainerAwareHttpKernelTest.php in vendor/symfony/http-kernel/Tests/DependencyInjection/ContainerAwareHttpKernelTest.php

DebugHandlersListenerTest.php in vendor/symfony/http-kernel/Tests/EventListener/DebugHandlersListenerTest.php

EventDispatcherTest.php in vendor/symfony/event-dispatcher/Tests/EventDispatcherTest.php

EventTest.php in vendor/symfony/event-dispatcher/Tests/EventTest.php

HttpKernelTest.php in vendor/symfony/http-kernel/Tests/HttpKernelTest.php

InlineFragmentRendererTest.php in vendor/symfony/http-kernel/Tests/Fragment/InlineFragmentRendererTest.php

RedirectResponseSubscriberTest.php in core/tests/Drupal/Tests/Core/EventSubscriber/RedirectResponseSubscriberTest.php

Contains \Drupal\Tests\Core\EventSubscriber\RedirectResponseSubscriberTest.

RequestDataCollectorTest.php in vendor/symfony/http-kernel/Tests/DataCollector/RequestDataCollectorTest.php

ResponseListenerTest.php in vendor/symfony/http-kernel/Tests/EventListener/ResponseListenerTest.php

SurrogateListenerTest.php in vendor/symfony/http-kernel/Tests/EventListener/SurrogateListenerTest.php

TestEventDispatcher.php in vendor/symfony/http-kernel/Tests/Fixtures/TestEventDispatcher.php

TestHttpKernel.php in vendor/symfony/http-kernel/Tests/TestHttpKernel.php

TestHttpKernel.php in vendor/symfony/http-kernel/Tests/HttpCache/TestHttpKernel.php

TestMultipleHttpKernel.php in vendor/symfony/http-kernel/Tests/HttpCache/TestMultipleHttpKernel.php

TraceableEventDispatcherTest.php in vendor/symfony/event-dispatcher/Tests/Debug/TraceableEventDispatcherTest.php

TraceableEventDispatcherTest.php in vendor/symfony/http-kernel/Tests/Debug/TraceableEventDispatcherTest.php