The new widgets were spotted by 9to5Google, and if you've got a Samsung Galaxy S22 or Samsung Galaxy S22 Ultra then they'll probably look awfully familiar: they're the same widgets that arrived in Samsung's One UI 4.1, which took the standard Android 12 widgets and made them better.
According to 9to5Google the new widgets come in three sizes, two of which are resizable: 2x2, which you can't resize, and 4x1 and 4x2, which you can resize to the width of your screen. Long-pressing on a widget brings up the customisation options.
What's so smart about Smart Widgets?
The "smart" bit of these Smart Widgets is that you can stack them. That means a widget works rather like a deck of cards, enabling you to swipe to see different ones. That's particularly handy for widgets that you want fast access to but don't want to dedicate screen space to permanently; instead of having a screen full of widgets you can park multiple ones in a single space and see whatever one you need whenever you need it.
Apple has a similar feature on the iPad, which I use a lot: it means I can swap between my calendar, which tells me where I should be, my maps widget, which shows me how and when to get there, and my to-do widget, which tells me what I'm supposed to be doing. You might find that Smart Widgets are a handy feature for putting your media player widget, your news widget and your weather widget in one place, or for anything else that enables you to see more information without needing more screen space.
The new Smart Widgets feature appeared in the March security update, which began rolling out to phones a few weeks ago and which is now appearing on Galaxy Tab S7 and S8 models. If you've got it you should now see Smart Widgets in the Widgets menu; if you haven't, go into Settings > Software Update to download the update manually.