diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
index b4d472a..32c8266 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
@@ -291,19 +291,7 @@ public function toArray() {
   }
 
   /**
-   * Gets the config entity properties to export.
-   *
-   * If declared on the entity_type annotation 'config_export' this is used.
-   * Otherwise, configuration schema is checked.
-   *
-   * @return array
-   *   A list of entity properties.
-   *
-   * @throws \Drupal\Core\Config\Schema\SchemaIncompleteException
-   *   Exception thrown when there is no 'config_export' annotation and there is
-   *   no config schema.
-   *
-   * @todo Remove underscore in Drupal 9.
+   * {@inheritdoc}
    */
   public function _getPropertiesToExport() {
     /** @var \Drupal\Core\Config\Entity\ConfigEntityTypeInterface $entity_type */
diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityInterface.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityInterface.php
index 248701e..3bfb1ba 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityInterface.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityInterface.php
@@ -217,4 +217,21 @@ public function trustData();
    */
   public function hasTrustedData();
 
+  /**
+   * Gets the config entity properties to export.
+   *
+   * If declared on the entity_type annotation 'config_export' this is used.
+   * Otherwise, configuration schema is checked.
+   *
+   * @return array
+   *   A list of entity properties.
+   *
+   * @throws \Drupal\Core\Config\Schema\SchemaIncompleteException
+   *   Exception thrown when there is no 'config_export' annotation and there is
+   *   no config schema.
+   *
+   * @todo Remove underscore in Drupal 9.
+   */
+  public function _getPropertiesToExport();
+
 }