Swiss privacy technology firm Proton AG has filed a lawsuit against Apple Inc. in the United States, accusing the iPhone maker of engaging in anticompetitive practices through its App Store policies and commission fees. Proton, known for its privacy-focused applications such as Proton Mail, alleges that Apple's App Store model constitutes illegal monopolization by imposing 'artificial and arbitrary' fees and maintaining a locked system that restricts competition. This legal action adds Proton to a growing list of app developers challenging Apple's control over app distribution and payment processing on iOS devices, arguing that the current system is designed to enrich Apple at the expense of developers and consumers.