atoti.Session.widget in JupyterLab.
Install it in the Python environment running the Jupyter Server hosting JupyterLab (not necessarily the one running the notebook kernel).
The jupyterlab extra is available on each atoti package:
atoti[jupyterlab].atoti-client[jupyterlab], for a client only environment.atoti-server[jupyterlab], for a server only environment.