11 files declare their use of YamlFormTidy in YAML Form 8

DebugYamlFormHandler.php in tests/modules/yamlform_test/src/Plugin/YamlFormHandler/DebugYamlFormHandler.php

yamlform.drush.inc in drush/yamlform.drush.inc

YAML Form module drush commands.

yamlform.theme.inc in includes/yamlform.theme.inc

Preprocessors and helper functions to make theming easier.

yamlform.translation.inc in includes/yamlform.translation.inc

YAML Form module translation hooks.

YamlFormAdminSettingsTest.php in src/Tests/YamlFormAdminSettingsTest.php

YamlFormCodeMirror.php in src/Element/YamlFormCodeMirror.php

YamlFormElementAttributes.php in src/Element/YamlFormElementAttributes.php

YamlFormElementStates.php in src/Element/YamlFormElementStates.php

YamlFormEntityExportForm.php in modules/yamlform_devel/src/Form/YamlFormEntityExportForm.php

YamlFormTidyTest.php in tests/src/Unit/YamlFormTidyTest.php

YamlYamlFormExporter.php in src/Plugin/YamlFormExporter/YamlYamlFormExporter.php