Neos\Flow\Session\Data

The session identifier that in a string form is written in the session cookie and identifies a SessionMetadata object from the SessionMetaDataStore that represents a stored session without the key value store.

The StorageIdentifier is used by the SessionKeyValueStore to write / retrieve th values for the given session. The StorageIdentifier is a secret of the server session and is never exposed to the outside. The StorageIdentifier stays the same if a Session gets a new SessionIdentifier (renewId).