Sources for what? The pareto frontier of LLMs? How Google is pretty much on the line with most of their LLM products? Or this particular model? For the first two you need to look for size/cost vs. accuracy charts. There are tons of them floating around. For the latter there is not much official info except what you can infer by analyzing the weights.bin file that Chrome downloads. But it does mention Gemini in there, so it seems pretty obvious that it is from their proprietary line of models.