16 files declare their use of ThemeManagerInterface

AssetResolver.php in core/lib/Drupal/Core/Asset/AssetResolver.php
BlockListBuilder.php in core/modules/block/src/BlockListBuilder.php
BlockRepository.php in core/modules/block/src/BlockRepository.php
CurrentThemeCondition.php in core/modules/system/src/Plugin/Condition/CurrentThemeCondition.php
ElementInfoManager.php in core/lib/Drupal/Core/Render/ElementInfoManager.php
FilteredPluginManagerTrait.php in core/lib/Drupal/Core/Plugin/FilteredPluginManagerTrait.php
FilteredPluginManagerTraitTest.php in core/tests/Drupal/Tests/Core/Plugin/FilteredPluginManagerTraitTest.php
FormBuilder.php in core/lib/Drupal/Core/Form/FormBuilder.php
LibraryDiscoveryCollector.php in core/lib/Drupal/Core/Asset/LibraryDiscoveryCollector.php
LibraryDiscoveryParser.php in core/lib/Drupal/Core/Asset/LibraryDiscoveryParser.php
MenuTestController.php in core/modules/system/tests/modules/menu_test/src/Controller/MenuTestController.php
PlaceBlockPageVariant.php in core/modules/block_place/src/Plugin/DisplayVariant/PlaceBlockPageVariant.php
Renderer.php in core/lib/Drupal/Core/Render/Renderer.php
ThemeCacheContext.php in core/lib/Drupal/Core/Cache/Context/ThemeCacheContext.php
ThemeSettingsForm.php in core/modules/system/src/Form/ThemeSettingsForm.php
TwigExtension.php in core/lib/Drupal/Core/Template/TwigExtension.php

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