Facebook claims that Apple blocked an update that would have informed users of Apple's practice of taking 30% of all in-app purchases. The update, which introduces a tool allowing businesses to sell tickets to online events, originally notified users of Apple's policy. The update was only allowed on the App Store after that wording was removed.
https://www.notebookcheck.net/Apple-rejected-update-for-Facebook-app-that-informed-users-of-Apple-s-30-cut-of-in-app-purchases.490426.0.html