17 files declare their use of ByteSizeMarkup

ByteSizeMarkupTest.php in core/tests/Drupal/Tests/Core/StringTranslation/ByteSizeMarkupTest.php
common.inc in core/includes/common.inc
Common functions that many Drupal modules will need to reference.
editor.admin.inc in core/modules/editor/editor.admin.inc
Administration functions for editor.module.
file.module in core/modules/file/file.module
Defines a "managed_file" Form API field and a "file" field for Field module.
FileFieldValidateTest.php in core/modules/file/tests/src/Functional/FileFieldValidateTest.php
FileItem.php in core/modules/file/src/Plugin/Field/FieldType/FileItem.php
FileSize.php in core/modules/file/src/Plugin/Field/FieldFormatter/FileSize.php
FileSize.php in core/modules/views/src/Plugin/views/field/FileSize.php
FileSizeLimitConstraintValidator.php in core/modules/file/src/Plugin/Validation/Constraint/FileSizeLimitConstraintValidator.php
FileTokenReplaceTest.php in core/modules/file/tests/src/Functional/FileTokenReplaceTest.php
FileWidgetAjaxController.php in core/modules/file/src/Controller/FileWidgetAjaxController.php
FormAjaxSubscriber.php in core/lib/Drupal/Core/Form/EventSubscriber/FormAjaxSubscriber.php
MigrateExecutable.php in core/modules/migrate/src/MigrateExecutable.php
system.install in core/modules/system/system.install
Install, update and uninstall functions for the system module.
TableFormatter.php in core/modules/file/src/Plugin/Field/FieldFormatter/TableFormatter.php
umami.theme in core/profiles/demo_umami/themes/umami/umami.theme
Functions to support theming in the Umami theme.
UploadedFileConstraintValidator.php in core/modules/file/src/Validation/Constraint/UploadedFileConstraintValidator.php

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