--- /dev/null
+<?php
+
+namespace Drupal\ctools\Plugin;
+use Drupal\Component\Plugin\Discovery\CachedDiscoveryInterface;
+use Drupal\Core\Plugin\Context\ContextAwarePluginManagerInterface;
+
+/**
+ * Provides the Relationship plugin manager.
+ */
+interface RelationshipManagerInterface extends ContextAwarePluginManagerInterface, CachedDiscoveryInterface {}