9 files declare their use of EnhancerInterface

EntityBundleRouteEnhancer.php in core/lib/Drupal/Core/Entity/Enhancer/EntityBundleRouteEnhancer.php
EntityRevisionRouteEnhancer.php in core/lib/Drupal/Core/Routing/Enhancer/EntityRevisionRouteEnhancer.php
EntityRouteEnhancer.php in core/lib/Drupal/Core/Entity/Enhancer/EntityRouteEnhancer.php
FormRouteEnhancer.php in core/lib/Drupal/Core/Routing/Enhancer/FormRouteEnhancer.php
LayoutTempstoreRouteEnhancer.php in core/modules/layout_builder/src/Routing/LayoutTempstoreRouteEnhancer.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
RouterUnsupportedTest.php in core/tests/Drupal/Tests/Core/Routing/RouterUnsupportedTest.php

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