Google Chrome silently installed a 4GB AI model on devices without consent

An OptGuideOnDeviceModel directory and a roughly 4GB weights.bin file were created in a Chrome user profile, presented as on-device Gemini Nano weights.

An audit of a new profile on Apple Silicon, cross-referencing .fseventsd, Local State, ChromeFeatureState, and GoogleUpdater logs, captured a flow in which the model directory was created, unpacked, and finally moved automatically over 14 minutes 28 seconds on April 24, 2026.

Key evidence is as follows.

• The download began without any user consent prompt or explicit settings checkbox.
• The OnDeviceModelBackgroundDownload flag was interpreted as what triggered the silent download.
• Local State retained traces of model validation results and eligibility determinations related to optimization_guide.on_device, such as vram_mb: "36864".
• The structure was explained as GoogleUpdater first receiving a control component, after which Chrome's internal OnDeviceModelComponentInstaller actually fetches the multi-GB weights from a CDN.

It also distinguished that Chrome 147's AI Mode pill is a cloud-based surface that queries Google's servers, not on-device Nano. Nano was described as being used for separate features such as Help me write, tab group AI suggestions, smart paste, and page summarization.

The piece pointed out that this deployment method could conflict with the transparency and minimization principles of ePrivacy and GDPR, and that bandwidth, power, and carbon costs would be significant at a deployment scale of hundreds of millions of devices. The core criticism is that the pathway for users to turn off or delete the download is not sufficiently exposed.