8 files declare their use of EnhancerInterface

EntityRevisionRouteEnhancer.php in core/lib/Drupal/Core/Routing/Enhancer/EntityRevisionRouteEnhancer.php
EntityRouteEnhancer.php in core/lib/Drupal/Core/Entity/Enhancer/EntityRouteEnhancer.php
FieldUiRouteEnhancer.php in core/modules/field_ui/src/Routing/FieldUiRouteEnhancer.php
FormRouteEnhancer.php in core/lib/Drupal/Core/Routing/Enhancer/FormRouteEnhancer.php
ParamConversionEnhancer.php in core/lib/Drupal/Core/Routing/Enhancer/ParamConversionEnhancer.php
ResourceVersionRouteEnhancer.php in core/modules/jsonapi/src/Revisions/ResourceVersionRouteEnhancer.php
RouteEnhancer.php in core/modules/jsonapi/src/Routing/RouteEnhancer.php
RouteEnhancerInterface.php in core/lib/Drupal/Core/Routing/Enhancer/RouteEnhancerInterface.php

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