If you don’t have a lot of experience with your Wear OS watch (if you don’t want to miss it much), Tiles is a collection of screens that appear in a carousel that you can swipe from on the watch face. Easy access to information (e.g. weather or fitness stats) or tasks (e.g. timer).
Tiles in Wear OS.
Until now, only first-party apps from Google and OEMs have been able to use Tiles. Given that access to third-party apps is the USP of Wear OS, it’s surprising that Google didn’t wake up earlier. But don’t get too excited, as these custom tiles will only be available to users later this spring with a corresponding Wear OS platform update.
Interested developers are newly announced Jetpack Tiles library. Also, Google has posted a list of best practices to help you make the ideal one.