7 files declare their use of SchemaIncompleteException in Drupal 9

ConfigEntityBase.php in core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php

ConfigEntityBaseUnitTest.php in core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php

Contains \Drupal\Tests\Core\Config\Entity\ConfigEntityBaseUnitTest.

ConfigSchemaChecker.php in core/lib/Drupal/Core/Config/Development/ConfigSchemaChecker.php

LayoutBuilderEntityViewDisplayTest.php in core/modules/layout_builder/tests/src/Kernel/LayoutBuilderEntityViewDisplayTest.php

SchemaConfigListenerTestTrait.php in core/tests/Drupal/Tests/Traits/Core/Config/SchemaConfigListenerTestTrait.php

SchemaConfigListenerWebTest.php in core/modules/config/tests/src/Functional/SchemaConfigListenerWebTest.php

SchemaListenerController.php in core/modules/config/tests/config_test/src/SchemaListenerController.php