It tracks interaction data according to a support article: Mozilla reveals that it assigns a unique ID per app, but does not get access to the 'DeviceID, AdvertisingID or Firefox client ID'.

Core points focus on the use of a third-party for data collection and the transfer and storage of the data in the USA. The organization has been criticized by privacy advocates for integration of Leanplum in some of its products. About 10% of Firefox mobile users from the United States with English set as the default language have Leanplum enabled currently according to this doc. Mozilla describes Leanplum as a mobile-marketing vendor on a support page, which it uses to 'test different features and experiences, as well as provide customized messages and recommendations to improve' user experiences.

Two new entries on the official GitHub project page highlight that Leanplum integration will be removed because Mozilla won't renew the contract with the company. Mozilla will remove the Leanplum integration of its mobile web browser Firefox for Android and iOS soon.

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