NotebookLM

Google notebook+LLM app https://notebooklm.google/

early 2025 - has greatly increased how much content you can load as context

Steven Johnson is effectively the Product Manager, or at least Onsite Customer: (2023-10-19) Johnson Introducing NotebookLM

https://golden.com/wiki/NotebookLM-AN95E4X

You can add a Note by typing or pasting text, and then convert that Note into a Source. You can do this either with other Sources already added, or start a new Notebook from scratch by adding a Note and converting it into Source. By doing so, you create a valuable reference without relying on external documents. Working entirely within the NotebookLM editor gives you full control over the information and provides immediate access to AI-driven analysis.