| ChecksumCalculatorInterface | Interface for adapters that support checksum calculation. |
| FileFactoryInterface | Interface for a class responsible for file creation. |
| ListKeysAwareInterface | Interface that adds native support for listing keys to an adapter. |
| MetadataSupporterInterface | Interface that adds support for file metadata management. |
| MimeTypeProviderInterface | Interface that adds MIME type detection support to an adapter. |
| SizeCalculatorInterface | Interface that adds size calculation support to an adapter. |
| StreamFactoryInterface | Interface for the stream creation class. |