8 files declare their use of OptionsProviderInterface in Zircon Profile 8.0

AllowedValuesConstraintValidator.php in core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/AllowedValuesConstraintValidator.php

Contains \Drupal\Core\Validation\Plugin\Validation\Constraint\AllowedValuesConstraintValidator.

BaseFieldDefinition.php in core/lib/Drupal/Core/Field/BaseFieldDefinition.php

Contains \Drupal\Core\Field\BaseFieldDefinition.

BooleanItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/BooleanItem.php

Contains \Drupal\Core\Field\Plugin\Field\FieldType\BooleanItem.

EntityReferenceItem.php in core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php

Contains \Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem.

FieldStorageConfig.php in core/modules/field/src/Entity/FieldStorageConfig.php

Contains \Drupal\field\Entity\FieldStorageConfig.

FilterAPITest.php in core/modules/filter/src/Tests/FilterAPITest.php

Contains \Drupal\filter\Tests\FilterAPITest.

FilterFormat.php in core/modules/filter/src/Plugin/DataType/FilterFormat.php

Contains \Drupal\filter\Plugin\DataType\FilterFormat.

ListItemBase.php in core/modules/options/src/Plugin/Field/FieldType/ListItemBase.php

Contains \Drupal\options\Plugin\Field\FieldType\ListItemBase.