In Xcode, I created some HTML help files and put them in a folder, like this:

But when Xcode builds the final app package, it flattens the folder structure.
ls ~/Library/Developer/Xcode/DerivedData/.../Build/Products/Debug/MyApp.app/Contents/Resources
... help.css help.en.html
And the following code crashes, because it expected a subdirectory:
let url = Bundle.main.url(forResource: "help.en", withExtension: "html", subdirectory: "Help")!
Is there a way to make it copy the directory structure to the output? I will have more files and I don't want to think about name clashes.