I think this is more like fine tuning an existing model to recognize features you specifically intend it to, and be light enough to run locally in a browser.
It's not even fine tuning, it's creating a model from scratch. This isn't like our modern huge models either, these tiny single-purpose models have been around for ages and are quite versatile. They're so small you can't just easily run them in the browser, but train them effectively, which is what this project lets you play around with! Super cool stuff.