How to build a Help view with hierarchical table of contents ?

In the Keynote/Numbers/Pages apps for iPhone, there is a Help menu item for presenting a Help modal view.

The view has a button for showing the hierarchical table of contents, and a field for searching the Help pages.

How is such a Help modal view built through SwiftUI ?

In which format is the Help content stored ?

I think this should help, at least for creating the hierarchical table: https://levelup.gitconnected.com/swiftui-hierarchical-table-2-ways-c5b734438e17

The Keynote/Numbers/Pages apps for iPhone have a Help modal view that is very neat.

Firstly I would like to know the format in which the Help content is stored.

The “Apple Help Book” format is used for the macOS apps, but which format is used for the iOS apps ?

Secondly I would like to know which SwiftUI API is used to build such a Help modal view.

Where to find a SwiftUI example that is based on the same storage format ?

How to build a Help view with hierarchical table of contents ?
 
 
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