33 files declare their use of WebformArrayHelper in Webform 6.x

Checkboxes.php in src/Plugin/WebformElement/Checkboxes.php

DateBase.php in src/Plugin/WebformElement/DateBase.php

OptionsBase.php in src/Plugin/WebformElement/OptionsBase.php

Select.php in src/Plugin/WebformElement/Select.php

SettingsWebformHandler.php in src/Plugin/WebformHandler/SettingsWebformHandler.php

webform.install.update.inc in includes/webform.install.update.inc

Archived Webform update hooks.

WebformAdminConfigElementsForm.php in src/Form/AdminConfig/WebformAdminConfigElementsForm.php

WebformAdminConfigFormsForm.php in src/Form/AdminConfig/WebformAdminConfigFormsForm.php

WebformArrayHelperTest.php in tests/src/Unit/Utility/WebformArrayHelperTest.php

WebformCompositeBase.php in src/Plugin/WebformElement/WebformCompositeBase.php

WebformCompositeFormElementTrait.php in src/Element/WebformCompositeFormElementTrait.php

WebformElementBase.php in src/Plugin/WebformElementBase.php

WebformElementComposite.php in src/Element/WebformElementComposite.php

WebformElementStates.php in src/Element/WebformElementStates.php

WebformEntityConditionsManager.php in src/WebformEntityConditionsManager.php

WebformEntityElementsValidator.php in src/WebformEntityElementsValidator.php

WebformEntitySettingsFormForm.php in src/EntitySettings/WebformEntitySettingsFormForm.php

WebformExcludedElements.php in src/Element/WebformExcludedElements.php

WebformHelpManager.php in src/WebformHelpManager.php

WebformImageSelectImagesForm.php in modules/webform_image_select/src/WebformImageSelectImagesForm.php

WebformLibrariesManager.php in src/WebformLibrariesManager.php

WebformOptionsCustom.php in modules/webform_options_custom/src/Element/WebformOptionsCustom.php

WebformOptionsForm.php in src/WebformOptionsForm.php

WebformSubmissionConditionsValidator.php in src/WebformSubmissionConditionsValidator.php

WebformSubmissionDevelGenerateTrait.php in src/Plugin/DevelGenerate/WebformSubmissionDevelGenerateTrait.php

WebformSubmissionForm.php in src/WebformSubmissionForm.php

WebformSubmissionListBuilder.php in src/WebformSubmissionListBuilder.php

WebformTableTrait.php in src/Plugin/WebformElement/WebformTableTrait.php

WebformTranslationConfigManager.php in src/WebformTranslationConfigManager.php

WebformTranslationManager.php in src/WebformTranslationManager.php

webform_bootstrap.module in modules/webform_bootstrap/webform_bootstrap.module

Helps support Webform to Bootstrap integration.

webform_cards.module in modules/webform_cards/webform_cards.module

Provides a 'Card' container element for clientside multistep form pagination.

webform_examples_accessibility.module in modules/webform_examples_accessibility/webform_examples_accessibility.module

Provides example webforms for reviewing and testing accessibility.