> You create content for the Swift Playgrounds app by writing playground books. Like traditional books, playground books are made up of chapters and pages. Unlike traditional books, they include executable Swift code that displays the results live, right on the page.
> Swift Playgrounds subscriptions, like podcasts, are a sequence of episodic content arranged in an order that builds knowledge while allowing more advanced learners to skip content. Subscriptions exist on the internet as feeds—downloadable lists of items that apps and websites can deal with. You publish a set of playgrounds as a feed that the Swift Playgrounds app can download, process, and display.
You publish them on your own website, via a JSON feed. No App Store review needed. You could treat it like a Jupyter Notebook, or an interactive story world - whatever you want.
[1] https://developer.apple.com/documentation/swift_playgrounds