Japan is joining the EU in forcing Apple to allow non-Webkit browsers on iOS. Following the EU’s Digital Markets Act, which came into effect last year, Japan now has the Smartphone Act.
This will come into effect by December, and will ban blocking or hindering alternative browser engines, in effect requiring that Apple allow any third-party browser using any rendering engine.
Apple must also refrain from practices that render the use of third-party browser engines impractical or commercially unviable. This is designed to avoid situations where Apple would technically comply but make it so hard for developers to actually use engines other than WebKit that in effect nothing would change for consumers.
Apple will also have to allow third-party browser engines access to the same APIs as WebKit. Apple can make other APIs available, but they may not be materially inferior to the ones Safari and WebKit use. Finally, the Smartphone Act mandates choice screens for browsers, where consumers are allowed to pick the one they like. Such a choice screen must be displayed “promptly after the first activation” of a device.