7 files declare their use of LibraryManagerInterface in Libraries API 8.3

AssetLibrary.php in src/ExternalLibrary/Asset/AssetLibrary.php

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

MultipleAssetLibrary.php in src/ExternalLibrary/Asset/MultipleAssetLibrary.php

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

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