14 files declare their use of ServiceProviderInterface in Drupal 8

ConfigOverride.php in core/lib/Drupal/Core/Installer/ConfigOverride.php

CoreServiceProvider.php in core/lib/Drupal/Core/CoreServiceProvider.php

DrupalKernel.php in core/lib/Drupal/Core/DrupalKernel.php

InstallerServiceProvider.php in core/lib/Drupal/Core/Installer/InstallerServiceProvider.php

JsonapiServiceProvider.php in core/modules/jsonapi/src/JsonapiServiceProvider.php

KernelTestBase.php in core/tests/Drupal/KernelTests/KernelTestBase.php

LayoutBuilderServiceProvider.php in core/modules/layout_builder/src/LayoutBuilderServiceProvider.php

NodeServiceProvider.php in core/modules/node/src/NodeServiceProvider.php

NormalInstallerServiceProvider.php in core/lib/Drupal/Core/Installer/NormalInstallerServiceProvider.php

RestServiceProvider.php in core/modules/rest/src/RestServiceProvider.php

RouterTestServiceProvider.php in core/modules/system/tests/modules/router_test_directory/src/RouterTestServiceProvider.php

SerializationServiceProvider.php in core/modules/serialization/src/SerializationServiceProvider.php

TestServiceProvider.php in core/tests/Drupal/KernelTests/TestServiceProvider.php

UpdateServiceProvider.php in core/lib/Drupal/Core/Update/UpdateServiceProvider.php