17 files declare their use of PluralTranslatableMarkup

ByteSizeMarkupTest.php in core/tests/Drupal/Tests/Core/StringTranslation/ByteSizeMarkupTest.php
FieldStorageReuseForm.php in core/modules/field_ui/src/Form/FieldStorageReuseForm.php
forum.install in core/modules/forum/forum.install
Install, update, and uninstall functions for the Forum module.
forum.post_update.php in core/modules/forum/forum.post_update.php
Contains post update functions.
LocalePluralFormatTest.php in core/modules/locale/tests/src/Functional/LocalePluralFormatTest.php
MigrateUpgradeImportBatch.php in core/modules/migrate_drupal_ui/src/Batch/MigrateUpgradeImportBatch.php
ModulesEnabledTrait.php in core/modules/system/src/Form/ModulesEnabledTrait.php
NumericField.php in core/modules/views/src/Plugin/views/field/NumericField.php
PermissionHandlerTest.php in core/modules/user/tests/src/Unit/PermissionHandlerTest.php
PluralTranslatableMarkupTest.php in core/tests/Drupal/Tests/Core/StringTranslation/PluralTranslatableMarkupTest.php
ResponseStatus.php in core/modules/system/src/Plugin/Condition/ResponseStatus.php
StatusReportPage.php in core/modules/system/src/Element/StatusReportPage.php
StatusTest.php in core/modules/system/tests/src/Functional/System/StatusTest.php
StringTranslationTraitTest.php in core/tests/Drupal/Tests/Core/StringTranslation/StringTranslationTraitTest.php
system.install in core/modules/system/system.install
Install, update and uninstall functions for the system module.
UnitTestCase.php in core/tests/Drupal/Tests/UnitTestCase.php
Update10101.php in core/modules/pgsql/src/Update10101.php

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