In a new blog post, computer scientist Alexander Hanff, aka the Privacy Guy, pulled back the curtain on this mysterious file. Named weights.bin, the file is being downloaded deep within the user data folder on many computers of Chrome users. The file itself is related to Gemini Nano, which Google is using as the on-device AI model for Chrome.

Though there's nothing risky or dangerous about the file, Hanff and others have expressed concerns that it's being downloaded without users' knowledge or permission. And if you delete the file, it eventually comes back, Hanff said. That by itself is hardly alarming; that's part of any software update. Rather, some of the criticism centers on the file's size. If you have ample hard disk space, then 4GB is likely not a big deal. But if you're running low, that big a file might chew up space you can't spare.

Traditionally, AI models like Gemini use the cloud to interact with you. Submit a request, ask a question, or kick off a conversation, and the AI taps into its online data and resources to respond. But that method can be slow and naturally requires that you be connected. By traveling between your device and the cloud, your data can also be exposed.

A trend has emerged in which companies are experimenting with locally stored LLMs (large language models). That not only speeds up the process, but it also means you can use the AI offline and more securely. Gemini Nano has already been in play on Google's own Pixel phones.