Combine Playground is a demonstration about Apple's Reactive Library. The intention is just to give you a short brief about differents componentes through the framework. Remember this is just a summary and not a complete reference go to apple's documentation if you want to know better o dive into a topic i will suggest you to take this book Combine by Tutorials cuz i based on this book and they explian better with more details. The ios project explains better time operators like throttle and debounce.
The structure of the playground is divided into 5 pages, every page has its own source code ready to be run, so you must remove the comment in which you want to see the output.