It does two things:
1. Turns your phone into a Google Slides remote. Open a link, swipe to advance, and read your speaker notes off the phone while you walk around the room. No dongle.
2. Lets several people drive the same live deck. You share one link. Up to 10 co-presenters can take control from any browser, on any device - no install and no account for anyone but the host.
I built it because Google locked native co-presenting behind paid Workspace tiers (Business Standard and up). If you're on a free account like most students or small teams - there's no way to hand off slide control mid-talk without the "next slide please".
Only the host installs a Chrome extension. Everyone else just opens a link. Your slides never leave Google Slides - the deck isn't uploaded or stored anywhere.
Happy to go into the technical side in the comments. Feedback very welcome.