Apple kicked off the iOS 13 portion of its keynote with a splashy demo of dark mode, a long-requested feature that darkens the iPhone's user interface, providing better contrast and easier viewing at times when you may not want to look at a bright screen.
What Apple didn't say during its presentation was that you'll be able to schedule dark mode to automatically activate at certain times of day. So if you want to switch over to dark mode before going to sleep or first thing in the morning, you can schedule it to do so.