As I wrote, it could be integrated into Photos. Or they could make a Clipboard app that integrates it. Apple isn’t foreign to turning OS-wide functionality into

As I wrote, it could be integrated into Photos. Or they could make a Clipboard app that integrates it. Apple isn’t foreign to turning OS-wide functionality into apps, like Files and Passwords and Preview. There’s also functionality made statefully available via Control Center and Notification Center, which do “draw UI elements on top of other apps”. There’s various ways this could be accomplished.