The new features let developers designate user interface elements as accessible, which makes it possible for screen readers and other assistive technology to understand what the object in question is. Accessible elements can also be given a label that a screen reader can use to describe what they are.
Applications using React Native can also figure out if the system they're running on has accessibility features turned on, and tweak the way their user interfaces are set up in order to make them more useful for people who are making use of assistive technology.
Using the new Accessibility API makes it possible for screen-reading programs like Apple's VoiceOver on the iPhone and Google's TalkBack on Android to tell users what an application looks like and how it works. That makes it possible for visually impaired users and other people using assistive features to more easily navigate and use those apps.
React and React Native are tools that help developers build user interfaces for the Web and mobile apps, respectively. React Native is a particularly important tool, since it works across both iOS and Android, and lets developers reuse code across different platforms. Now, it's possible for developers to build accessible apps across both mobile operating systems as well.
Facebook has already implemented the new accessibility technology in its own Ads Manager app for iOS and Android, which allows people to create and monitor ad campaigns for the social network from their mobile devices. The company has been making a push towards improving accessibility in its own apps, and recently enabled the Dynamic Type feature for users on iOS, which lets users make the text inside the app larger.