Firefox on Glean (FOG)

Firefox on Glean (FOG) is the name of the layer that integrates the Glean SDK into Firefox Desktop.

The Glean SDK is a data collection library built by Mozilla for use in its products. Like Telemetry, it can be used to (in accordance with our Privacy Policy) send anonymous usage statistics to Mozilla in order to make better decisions.

If you have any questions, please reach out to the team on