This is according to developer @CraftyDeano who posted an image of the new privacy icon that was discovered in the new iOS 11.3 beta. According to Apple’s information, the icon is said to appear only when an Apple app or feature is asking for your personal information, but Apple notes that this won’t happen all the time.
https://twitter.com/craftydeano/status/956235634154332168
It also seems that this new privacy icon feature will be arriving for macOS computers as well and it seems that the same rules apply there too. This is a welcome feature for those who want a bit more transparency in how our mobile devices are collecting our data. Presumably this new feature might have been spurred on from the backlash Apple faced over the throttling controversy.
One of the things Apple promised they would change is introduce new features in iOS that would make more transparent as to how well the user’s battery is performing. In the meantime in addition to this new privacy icon, iOS 11.3 is also expected to introduce the ability to allow users to disable the throttling feature.