I think it's a completely new UI that some people at Google built from scratch, which is much easier for them to do realtime sync with using their API (https://

I think it's a completely new UI that some people at Google built from scratch, which is much easier for them to do realtime sync with using their API (https://developers.google.com/google-apps/realtime/realtime-quickstart https://developers.google.com/google-apps/realtime/realtime-...). I think they felt there were also some usability issues with the standard Jupyter UI when sync was added in. (Source: I visited the group writing this a few years ago at Google and they showed me a demo which looked just like this.)