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Mozilla, like Google, is looking ahead to the end of Apple's WebKit rule

Work on a Gecko-based version of Firefox for iOS is underway, again

Updated Mozilla is planning for the day when Apple will no longer require its competitors to use the WebKit browser engine in iOS.

Mozilla conducted similar experiments that never went anywhere years ago but in October 2022 posted an issue in the GitHub repository housing the code for the iOS version of Firefox that includes a reference to GeckoView, a wrapper for Firefox's Gecko rendering engine.

Under the current Apple App Store Guidelines, iOS browser apps must use WebKit. So a Firefox build incorporating Gecko rather than WebKit currently cannot be distributed through the iOS App Store.

As we reported last week, Mozilla is not alone in anticipating an iOS App Store regime that tolerates browser competition. Google has begun work on a Blink-based version of Chrome for iOS.

The major browser makers – Apple, Google, and Mozilla – each have their own browser rendering engines. Apple's Safari is based on WebKit; Google's Chrome and its open source Chromium foundation is based on Blink (forked from WebKit a decade ago); and Mozilla's Firefox is based on Gecko.

Microsoft developed its own Trident rendering engine in the outdated Internet Explorer and a Trident fork called EdgeHTML in legacy versions of Edge but has relied on Blink since rebasing its Edge browser on Chromium code.

Browser rendering engines render text and images on screen. When browser engineers add new features or support new APIs, they often do so through rendering engine code additions, as can be seen from various Blink enhancements.

Sometimes Apple, Google, and Firefox agree on new features and work together and fix the issue, as with popover menus. Other times, the browser makers disagree and sulk as their codebases diverge.

Safari developed a reputation for lagging behind Chrome and Firefox. Apple, however, appears to be aware of the risk posed by regulators and has added more staff to the WebKit team to close the capabilities gap.

If Apple does allow other browser engines within iOS ecosystem, Google and Mozilla will be able to compete with Safari through technical differentiation that's already evident in the desktop versions of these browsers.

Open Web Advocacy, a developer lobbying group, last year issued a Walled Gardens report elaborating on the consequences of Apple's WebKit requirement. It described Apple's restrictions as anticompetitive self-preferencing.

"Apple is preventing the interoperable, standards-based web from becoming a viable alternative to the native proprietary ecosystems on offer from Apple and Google," the group's report argues.

"In the absence of competition, the poor state of Apple’s own browser and integration of webapps has the effect of pushing developers and users towards the gated ecosystem of the App Store."

While the requested Firefox for iOS settings page for toggling GeckoView could be for internal browser testing, it appears to be something more. The brief public discussion of the GitHub issue suggests Mozilla has anticipated that Apple's rules may change – something sought by Mozilla and others through ongoing regulatory lobbying.

Asked on December 12 by an open source contributor what release this is for, Laurie Marceau, senior software Developer at Mozilla, answered that it's "for a secondary project not in this repository."

The open source contributor then replies, "Thanks, can't wait until [the] EU clarifies [the] situation and we can have proper Gecko Firefox on iOS."

Marceau responds with a thumbs-up emoji. We asked Marceau to elaborate but we've not heard back. Mozilla did not immediately respond but said it might have something to say later. We will update this story if so.

On December 13 last year, it was reported that Apple was preparing to allow third-party app stores in iOS 17 – expected in Q3 2023 – to comply with the European Digital Markets Act. Those rules – and related concerns raised by other regulators – look likely to force Apple to drop its iOS WebKit requirement.

Apple, however, has made no public commitment to that effect and did not respond to The Register's request for comment.

This is not the first time Mozilla has prepared a Gecko-based version of Firefox for iOS. Ted Mielczarek, a former platform engineer at Mozilla, noted via Twitter that he has twice before been involved in Gecko ports to iOS, in 2010 and 2015.

Mozilla never forced the issue by asking a court to force Apple to distribute Gecko-based Firefox on iOS – a costly battle it might not win. But recently it showed public concern about the anticompetitive consequences of Apple's WebKit rule in a September 2022 report titled "Five Walled Gardens: Why Browsers are Essential to the Internet and How Operating Systems Are Holding Them Back."

If the EU Digital Markets act has the effect that has been predicted, there will be fewer walled gardens by the end of the year. But based on past experience don't hold your breath. ®

Updated to add

In an emailed statement, a Mozilla spokesperson said, "We abide by Apple's iOS app store policies, and are simply doing some exploratory work to understand the technical challenges for Gecko-based browsers on iOS if those policies were to change. We hope the day will come when people can freely decide to use the browser of their choice, including the opportunity to select the engine that underpins it."

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