--- /dev/null
+<?php
+
+namespace Drupal\layout_builder;
+
+/**
+ * Defines an interface for an object that stores layout sections for overrides.
+ *
+ * @internal
+ * Layout Builder is currently experimental and should only be leveraged by
+ * experimental modules and development releases of contributed modules.
+ * See https://www.drupal.org/core/experimental for more information.
+ */
+interface OverridesSectionStorageInterface extends SectionStorageInterface {
+
+ /**
+ * Returns the corresponding defaults section storage for this override.
+ *
+ * @return \Drupal\layout_builder\SectionStorageInterface
+ * The defaults section storage.
+ *
+ * @todo Determine if this method needs a parameter in
+ * https://www.drupal.org/project/drupal/issues/2936507.
+ */
+ public function getDefaultSectionStorage();
+
+}