15 files declare their use of LibraryInterface in Libraries API 8.3

AssetLibraryInterface.php in src/ExternalLibrary/Asset/AssetLibraryInterface.php

AssetLibraryType.php in src/Plugin/libraries/Type/AssetLibraryType.php

AttachableAssetLibraryRegistrationInterface.php in src/ExternalLibrary/Asset/AttachableAssetLibraryRegistrationInterface.php

DependentLibraryInterface.php in src/ExternalLibrary/Dependency/DependentLibraryInterface.php

InvalidLibraryDependencyException.php in src/ExternalLibrary/Exception/InvalidLibraryDependencyException.php

LibraryCreationListenerInterface.php in src/ExternalLibrary/Type/LibraryCreationListenerInterface.php

LibraryLoadingListenerInterface.php in src/ExternalLibrary/Type/LibraryLoadingListenerInterface.php

LibraryTypeBase.php in src/ExternalLibrary/Type/LibraryTypeBase.php

LibraryTypeKernelTestBase.php in tests/src/Kernel/LibraryTypeKernelTestBase.php

LocalLibraryInterface.php in src/ExternalLibrary/Local/LocalLibraryInterface.php

MultipleAssetLibraryInterface.php in src/ExternalLibrary/Asset/MultipleAssetLibraryInterface.php

MultipleAssetLibraryType.php in src/Plugin/libraries/Type/MultipleAssetLibraryType.php

PhpFileLibraryType.php in src/Plugin/libraries/Type/PhpFileLibraryType.php

RemoteLibraryInterface.php in src/ExternalLibrary/Remote/RemoteLibraryInterface.php

VersionedLibraryInterface.php in src/ExternalLibrary/Version/VersionedLibraryInterface.php