13 files declare their use of SandboxManagerBase

ApiController.php in core/modules/package_manager/tests/modules/package_manager_test_api/src/ApiController.php
CollectPathsToExcludeEvent.php in core/modules/package_manager/src/Event/CollectPathsToExcludeEvent.php
EventWithPackageListTrait.php in core/modules/package_manager/src/Event/EventWithPackageListTrait.php
FailureMarkerRequirementTest.php in core/modules/package_manager/tests/src/Functional/FailureMarkerRequirementTest.php
PackageManagerKernelTestBase.php in core/modules/package_manager/tests/src/Kernel/PackageManagerKernelTestBase.php
PreApplyEvent.php in core/modules/package_manager/src/Event/PreApplyEvent.php
PreCreateEvent.php in core/modules/package_manager/src/Event/PreCreateEvent.php
SandboxDirectoryValidatorTest.php in core/modules/package_manager/tests/src/Unit/SandboxDirectoryValidatorTest.php
SandboxEvent.php in core/modules/package_manager/src/Event/SandboxEvent.php
SandboxException.php in core/modules/package_manager/src/Exception/SandboxException.php
SandboxManagerBaseTest.php in core/modules/package_manager/tests/src/Unit/SandboxManagerBaseTest.php
SandboxManagerBaseTest.php in core/modules/package_manager/tests/src/Kernel/SandboxManagerBaseTest.php
StatusCheckEvent.php in core/modules/package_manager/src/Event/StatusCheckEvent.php

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