Apple Is Set to Unveil AR Upgrade, Software to Manage iPhone Use – Bloomberg:

Apple engineers have been working on an initiative dubbed Digital Health, a series of tools to help users monitor how much time they spend on their devices and inside of certain applications. These details will be bundled into a menu inside of the Settings app in iOS 12, the likely name of Apple’s refreshed mobile operating system, according to people familiar with the plans.

It sounds like this feature isn’t coming to MacOS where I spend 90-95% of my computing time. There are a lot of 3rd party Applications that allow you to track time and impose user-defined limits on how much time you spend browsing the web or using Twitter so I’m not too concerned, nor have I ever felt I needed that.