Apple launched the App Store in 2008, the year after Cydia arrived. The unofficial store allows users who jailbreak their iPhone and iPad to download apps and add features that Apple hasn’t necessarily approved.
Over time, Apple has made jailbreaking its devices more difficult and Cydia isn’t as prominent or popular as it once was. In 2010, Cydia developer Jay “Saurik” Freeman said 4.5 million users were searching the store for apps.
The suit follows a number of high-profile moves against Apple for similar reasons. Back in August, Epic Games sued Apple over its App Store rules after trying to bypass them. A coalition of companies, including Epic and Spotify, has formed to pressure Apple and Google into changing their app store practices. Apple is also under antitrust scrutiny from regulators in Europe and the US.