In the long contest between platform power and market fairness, a group of UK app developers has brought a £2 billion claim before the Competition Appeal Tribunal, alleging that Apple's 2021 App Tracking Transparency system — presented to the world as a shield for user privacy — was quietly engineered to disadvantage rivals in mobile advertising while insulating Apple's own services from the same constraints. The case, unfolding alongside regulatory scrutiny in five European nations, asks a question that will shape the digital economy for years: when a powerful gatekeeper writes the rules of p