80 files declare their use of UrlHelper

AjaxPageState.php in core/lib/Drupal/Core/StackMiddleware/AjaxPageState.php
AjaxPageStateTest.php in core/modules/system/tests/src/Functional/Render/AjaxPageStateTest.php
AjaxTest.php in core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxTest.php
AssetControllerBase.php in core/modules/system/src/Controller/AssetControllerBase.php
AssetOptimizationTest.php in core/tests/Drupal/FunctionalTests/Asset/AssetOptimizationTest.php
AssetResolver.php in core/lib/Drupal/Core/Asset/AssetResolver.php
batch.inc in core/includes/batch.inc
Batch processing API for processes to run in multiple HTTP requests.
BigPipeStrategy.php in core/modules/big_pipe/src/Render/Placeholder/BigPipeStrategy.php
BigPipeTest.php in core/modules/big_pipe/tests/src/Functional/BigPipeTest.php
BrowserTestBase.php in core/tests/Drupal/Tests/BrowserTestBase.php
ckeditor5.module in core/modules/ckeditor5/ckeditor5.module
claro.theme in core/themes/claro/claro.theme
Functions to support theming in the Claro theme.
comment.tokens.inc in core/modules/comment/comment.tokens.inc
Builds placeholder replacement tokens for comment-related data.
CommentTokenReplaceTest.php in core/modules/comment/tests/src/Functional/CommentTokenReplaceTest.php
ComponentPluginManager.php in core/modules/sdc/src/ComponentPluginManager.php
ComponentPluginManager.php in core/lib/Drupal/Core/Theme/ComponentPluginManager.php
ConfirmFormHelper.php in core/lib/Drupal/Core/Form/ConfirmFormHelper.php
contextual.module in core/modules/contextual/contextual.module
Adds contextual links to perform actions related to elements on a page.
ContextualLinks.php in core/modules/contextual/src/Plugin/views/field/ContextualLinks.php
Cookie.php in core/modules/user/src/Authentication/Provider/Cookie.php
CredentialForm.php in core/modules/migrate_drupal_ui/src/Form/CredentialForm.php
CssCollectionOptimizerLazy.php in core/lib/Drupal/Core/Asset/CssCollectionOptimizerLazy.php
CustomPageExceptionHtmlSubscriberTest.php in core/tests/Drupal/Tests/Core/EventSubscriber/CustomPageExceptionHtmlSubscriberTest.php
DbLogController.php in core/modules/dblog/src/Controller/DbLogController.php
DisplayPluginBase.php in core/modules/views/src/Plugin/views/display/DisplayPluginBase.php
DrupalKernel.php in core/lib/Drupal/Core/DrupalKernel.php
Endpoint.php in core/modules/media/src/OEmbed/Endpoint.php
FieldPluginBase.php in core/modules/views/src/Plugin/views/field/FieldPluginBase.php
FieldUI.php in core/modules/field_ui/src/FieldUI.php
FieldWebTest.php in core/modules/views/tests/src/Functional/Handler/FieldWebTest.php
FileUrlGenerator.php in core/lib/Drupal/Core/File/FileUrlGenerator.php
FilterProcessResult.php in core/modules/filter/src/FilterProcessResult.php
form.inc in core/includes/form.inc
Functions for form and batch generation and processing.
FormattableMarkup.php in core/lib/Drupal/Component/Render/FormattableMarkup.php
FormBuilder.php in core/lib/Drupal/Core/Form/FormBuilder.php
GotoAction.php in core/lib/Drupal/Core/Action/Plugin/Action/GotoAction.php
HandlerBase.php in core/modules/views/src/Plugin/views/HandlerBase.php
ImageStyle.php in core/modules/image/src/Entity/ImageStyle.php
install.core.inc in core/includes/install.core.inc
API functions for installing Drupal.
install.inc in core/includes/install.inc
API functions for installing modules and themes.
JsCollectionOptimizerLazy.php in core/lib/Drupal/Core/Asset/JsCollectionOptimizerLazy.php
LinkExternalProtocolsConstraintValidator.php in core/modules/link/src/Plugin/Validation/Constraint/LinkExternalProtocolsConstraintValidator.php
LinkExternalProtocolsConstraintValidatorTest.php in core/modules/link/tests/src/Unit/Plugin/Validation/Constraint/LinkExternalProtocolsConstraintValidatorTest.php
LinkItemSerializationTest.php in core/modules/link/tests/src/Kernel/LinkItemSerializationTest.php
LinkItemTest.php in core/modules/link/tests/src/Kernel/LinkItemTest.php
LocalAwareRedirectResponseTrait.php in core/lib/Drupal/Core/Routing/LocalAwareRedirectResponseTrait.php
locale.module in core/modules/locale/locale.module
MediaLibraryHooks.php in core/modules/media_library/src/Hook/MediaLibraryHooks.php
MenuLinkParent.php in core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php
MenuTreeStorage.php in core/lib/Drupal/Core/Menu/MenuTreeStorage.php
OpenModalDialogWithUrl.php in core/lib/Drupal/Core/Ajax/OpenModalDialogWithUrl.php
PagerParameters.php in core/lib/Drupal/Core/Pager/PagerParameters.php
PathPluginBase.php in core/modules/views/src/Plugin/views/display/PathPluginBase.php
PathValidator.php in core/lib/Drupal/Core/Path/PathValidator.php
PlaceholderGenerator.php in core/lib/Drupal/Core/Render/PlaceholderGenerator.php
Provider.php in core/modules/media/src/OEmbed/Provider.php
PublicStream.php in core/lib/Drupal/Core/StreamWrapper/PublicStream.php
RedirectDestination.php in core/lib/Drupal/Core/Routing/RedirectDestination.php
RedirectDestinationTest.php in core/tests/Drupal/Tests/Core/Routing/RedirectDestinationTest.php
RedirectResponseSubscriber.php in core/lib/Drupal/Core/EventSubscriber/RedirectResponseSubscriber.php
RequestSanitizer.php in core/lib/Drupal/Core/Security/RequestSanitizer.php
search.pages.inc in core/modules/search/search.pages.inc
SettingsCommand.php in core/lib/Drupal/Core/Ajax/SettingsCommand.php
system.module in core/modules/system/system.module
Configuration system that lets administrators modify the workings of the site.
TableSort.php in core/lib/Drupal/Core/Utility/TableSort.php
UiHelperTrait.php in core/tests/Drupal/Tests/UiHelperTrait.php
UnroutedUrlAssembler.php in core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php
Url.php in core/lib/Drupal/Core/Url.php
Url.php in core/lib/Drupal/Core/Render/Element/Url.php
UrlGenerator.php in core/lib/Drupal/Core/Routing/UrlGenerator.php
UrlHelperTest.php in core/tests/Drupal/Tests/Component/Utility/UrlHelperTest.php
UrlResolver.php in core/modules/media/src/OEmbed/UrlResolver.php
UrlTest.php in core/tests/Drupal/Tests/Core/UrlTest.php
UrlTest.php in core/modules/system/tests/src/Kernel/Common/UrlTest.php
UserLoginBlock.php in core/modules/user/src/Plugin/Block/UserLoginBlock.php
ViewAjaxController.php in core/modules/views/src/Controller/ViewAjaxController.php
ViewsForm.php in core/modules/views/src/Form/ViewsForm.php
WebDriverTestBase.php in core/tests/Drupal/FunctionalJavascriptTests/WebDriverTestBase.php
XssTest.php in core/tests/Drupal/Tests/Component/Utility/XssTest.php
XssUnitTest.php in core/tests/Drupal/KernelTests/Core/Common/XssUnitTest.php

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