Apple Watch version the Todo list app :-) on watchOS 3 everything runs locally! In the earlier version the database is stored on the iPhone.

There are two versions:

• WatchKit on iOS 8 (watchOS 1)
• watchOS 3 (basically working on watch, does not sync to phone at all)

There are also Xamarin docs for watchOS.

watch screenshots use Bezel courtesy of infinitapps :)