18 files declare their use of Environment

CKEditor5ImageController.php in core/modules/ckeditor5/src/Controller/CKEditor5ImageController.php
color.module in core/modules/color/color.module
Allows users to change the color scheme of themes.
Cron.php in core/lib/Drupal/Core/Cron.php
editor.admin.inc in core/modules/editor/editor.admin.inc
Administration functions for editor.module.
EditorImageDialog.php in core/modules/editor/src/Form/EditorImageDialog.php
EnvironmentTest.php in core/tests/Drupal/Tests/Component/Utility/EnvironmentTest.php
file.module in core/modules/file/file.module
Defines a "managed_file" Form API field and a "file" field for Field module.
FileItem.php in core/modules/file/src/Plugin/Field/FieldType/FileItem.php
FileUploadHandlerTest.php in core/modules/file/tests/src/Kernel/FileUploadHandlerTest.php
FileUploadResource.php in core/modules/file/src/Plugin/rest/resource/FileUploadResource.php
FormBuilder.php in core/lib/Drupal/Core/Form/FormBuilder.php
FunctionalTestSetupTrait.php in core/lib/Drupal/Core/Test/FunctionalTestSetupTrait.php
ImportForm.php in core/modules/locale/src/Form/ImportForm.php
LargeQueryTest.php in core/modules/mysql/tests/src/Kernel/mysql/LargeQueryTest.php
LegacyFileTest.php in core/modules/file/tests/src/Kernel/LegacyFileTest.php
node.module in core/modules/node/node.module
The core module that allows content to be submitted to the site.
system.install in core/modules/system/system.install
Install, update and uninstall functions for the system module.
TemporaryJsonapiFileFieldUploader.php in core/modules/jsonapi/src/Controller/TemporaryJsonapiFileFieldUploader.php

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