Drupal 8.0.0 beta 12. More info: https://www.drupal.org/node/2514176

core/lib/Drupal/Component/Discovery/DiscoverableInterface.php

@@ -0,0 +1,23 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Component\Discovery\DiscoverableInterface.
+ */
+
+namespace Drupal\Component\Discovery;
+
+/**
+ * Interface for classes providing a type of discovery.
+ */
+interface DiscoverableInterface {
+
+  /**
+   * Returns an array of discoverable items.
+   *
+   * @return array
+   *   An array of discovered data keyed by provider.
+   */
+  public function findAll();
+
+}