The main goal was privacy: the extension operates entirely client-side using chrome.storage. There are no external server calls, and aside from the regular Chrome's store analytics, there is no telemetry and no data collection.
I just opened up the source code. If anyone else finds the default Gemini UI cluttered, this might help.
Source: https://github.com/dlamarre-dev/GeminiFolders Web Store: https://chromewebstore.google.com/detail/gemini-folders/jffc...