How does web messaging maintain it's chat history

Does web messaging use solely the external participant to maintain Session Persistence, Asynchronous Communication and Message Threading? or does the Deployment ID also play a role?

Hello and thanks for reaching out. Session are bound to token provided during configure session

token (required) A guest-generated UUID used to access the session. This value is arbitrary to Genesys Cloud, but it must be unique as it grants access to a specific session.

Session are bound to deployments.

I hope this answer your question