Mozilla is also developing a non-WebKit browser for iOS

Web browsers and apps with web-browsing functionality must use "the appropriate WebKit framework and WebKit Javascript," according to App Store Review Guidelines. Browser companies appear to be exploring alternatives to using the browser engine approved by Apple to provide browsing on iOS, though.

Mozilla is reportedly working on a non-WebKit iOS browser, according to a new report from The Register. In October, Mozilla posted an issue in the GitHub repository hosting the code for the iOS version of Firefox that includes a reference to GeckoView, a wrapper for Firefox's Gecko rendering engine.

An open-source contributor asked in December what the purpose of the release was. Laurie Marceau, senior software Developer at Mozilla, said it's "for a secondary project not in this repository."

Google's Chromium team is also working on a new experimental browser for iOS based on Blink, instead of using Webkit as mandated by App Store policies, and now Mozilla is doing the same.

Changes to App Store policies

Apple's rule of requiring third-party browsers to use its WebKit engine might change. For example, the European Union is coming after Apple with the Digital Markets Act that will be applicable on May 2, 2023.

It would require companies such as Apple to offer alternatives to allow third-party app stores on its platforms and alternative payment systems. However, the WebKit-only requirement wouldn't constrain a third-party browser since other stores can set their own policies regarding app content.

Apple is already preparing to support third-party app stores on its platform by 2024 but some changes could appear in 2023 with the release of iOS 17.

If third-party browsers on Apple's mobile operating systems get clearance to use their engines, it will give Apple better competition to improve WebKit and offer more features to keep developers and others in the WebKit ecosystem.