Apple Developer News:

Following feedback from the European Commission and from developers, in these releases developers can develop and test EU-specific features, such as alternative browser engines, contactless apps, marketplace installations from web browsers, and marketplace apps, from anywhere in the world. Developers of apps that use alternative browser engines can now use WebKit in those same apps.

I just spent a few minutes trying to figure out how this works, but haven’t found it. If anyone can point me to the answer, let me know. It’s kind of bananas that EU-specific features couldn’t even be tested outside the EU until now.