Vienna-based advocacy organization NOYB announced on Wednesday that it has lodged a complaint with the Austrian data protection authority against Mozilla, alleging that the Firefox browser developer is tracking user behavior on websites without obtaining proper consent.

NOYB (None Of Your Business), a digital rights organization established by privacy advocate Max Schrems, claims that Mozilla has activated a feature known as privacy preserving attribution (PPA), which effectively transforms the browser into a tracking mechanism for websites without adequately informing users.

A spokesperson for NOYB stated to Reuters, “Mozilla's limited testing of PPA is part of our initiative to enhance advertising practices by offering technical alternatives. These methods ensure that no party, including Mozilla, can identify individuals or their browsing habits.”

Although this approach may be less intrusive than unrestricted tracking, NOYB argues that it still violates user rights under EU privacy regulations, noting that Firefox has enabled this feature by default.

“It is disappointing that an organization like Mozilla assumes users are incapable of making informed choices,” remarked Felix Mikolasch, a data protection attorney at NOYB. “Users deserve the ability to opt in or out, and this feature should not have been activated by default.”

Once a leading choice for users due to its strong privacy features, open-source Firefox now trails behind market leaders such as Google’s Chrome, Apple’s Safari, and Microsoft’s Edge, holding only a small single-digit market share.

NOYB is calling on Mozilla to provide transparency regarding its data processing practices, implement an opt-in system, and erase all unlawfully processed data belonging to millions of affected users.

In June, NOYB also filed a complaint against Alphabet for allegedly tracking users of its Chrome browser and has submitted numerous complaints against major tech companies, some resulting in significant fines.