7 files declare their use of TraversableTypedDataInterface

ConfigMapperManager.php in core/modules/config_translation/src/ConfigMapperManager.php
ListElement.php in core/modules/config_translation/src/FormElement/ListElement.php
LocaleConfigManager.php in core/modules/locale/src/LocaleConfigManager.php
SchemaCheckTrait.php in core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
TypedConfigInterface.php in core/lib/Drupal/Core/Config/Schema/TypedConfigInterface.php
TypedConfigManager.php in core/lib/Drupal/Core/Config/TypedConfigManager.php
ValidKeysConstraintValidatorTest.php in core/tests/Drupal/KernelTests/Core/TypedData/ValidKeysConstraintValidatorTest.php

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