There is, however, one new feature for VoiceOver users: a new option called ‘Accessibility Events’ located at Settings > General > Accessibility > VoiceOver > Web. This option is enabled by default, with Apple saying that Accessibility Events:

… allow websites to customize their behaviour for assistive technologies, like VoiceOver. Enabling Accessibility Events may reveal whether an assistive technology is active on your iPhone.

We’re currently unaware of any websites which take advantage of this facility, so do please let us know in the comments if you know more about this feature and any websites where it can be seen in action.

From Applevis:

This is just as bad of an idea as Google’s “ask-for-alt-text” feature. I will definitely be turning this off when I update my devices because sorry fellow developeres, you cannot haz that data. These settings, including the automatic opt-in, also apply to Mac OS Mojave, (OSX 10.14.4). This version of OSX was released on the same day as iOS 12.2. I’ll also be encouraging everyone else, (in the strongest possible terms), to do the same. Seriously, why is it so difficult to just make websites accessible in the first place? Why do we have to keep having this conversation? We’ve seen what happens when data is managed irresponsibly, (and that’s putting it lightly), and as neither a society nor an industry are we even close to equipped to handle something as sensitive as screen reader tetection with any kind of care. What’s Apple going to do, release some ethical guidelines? Even if they did this, how are they supposed to enforce them? And never mind developers screwing this up by using it as it probably wasn’t intended. It happened with HTML, it’ll happen with screen reader detection too.

If, like me, you are concerned about your privacy with regard to your disability, you’ll need to explicitly opt out, on both iOS and OSX. Consult either your device’s documentation, (VoiceOver for iOS or VoiceOver for the Mac), or a suitable book written for assistive technology users by assistive technology users. The one I wholeheartedly recommend is iOS Access for All: Your Comprehensive Guide to Accessibility for iPad, iPhone, and iPod Touch, by Shelly Brisbin.