"self" refers to the object that the func is contained in. But your code shows no such object. Perhaps you have you omitted the crucial code? ...but if these funcs are global, then there is indeed no "self".

You should take ownership of your app. Use your Apple Developer account, and add your Developer as a member of your Team (with an appropriate role). (If the app already exists under another account, then it will need to be transferred.) Use your GitHub (or equivalent) source code repository, and add your Developer to that. So everything is hosted/sourced on an account that you control.

If the range restriction is with peer-to-peer WiFi, then perhaps consider using WiFi, but not peer-to-peer, with a battery-powered router half-way between the two iPhones?

On creating a new project, if Interface is set to "SwiftUI", then the only available language will be "Swift". Setting Interface to "Storyboard" gives the choice of Swift or Objective-C

How are you adding the files to the Project? For example, have you tried (from Xcode): Right-click on Project "Add Files to {your Project}..." ...then navigating to "FileOut.dat"

Try following this guide: https://www.hackingwithswift.com/example-code/uikit/how-to-change-your-app-icon-dynamically-with-setalternateiconname

Following on from my original answer... The json response looks quite complicated, so I made a very simple test for the decoding: struct Food: Decodable { let description: String } struct FDCResponse: Decodable { let foods: [Food] } You have: self.FDCResults = decodedResponse.FDCResults ...and I don't know the structure of your FDCResults, so I just: print("decodedResponse: \(decodedResponse)") // FDCResponse ...and I got: decodedResponse: FDCResponse(foods: [DataTest.Food(description: "Apples, fuji, with skin, raw"), DataTest.Food(description: "Apples, gala, with skin, raw"), DataTest.Food(description: "Apples, honeycrisp, with skin, raw"), DataTest.Food(description: "Apples, granny smith, with skin, raw"), DataTest.Food(description: "Apples, red delicious, with skin, raw")])

Identifiers can be created automatically (e.g. from Xcode) or manually (on Apple Developer). The "IDENTIFIER" is the Bundle ID of the app (usually a reverse-domain name style string). Once an Identifier has been created (on Apple Developer), it's "IDENTIFIER" is fixed, and cannot be edited. You can only "Remove" it, or change it's "Description", or it's "Capabilities".

Does your project include any external frameworks/dependencies?

If you use an NSSavePanel to allow the user to choose the save location, that will implicitly grant the write permission. "When the user saves the document, macOS adds the saved file to the app's sandbox (if necessary) so that the app can write to the file."

If you're using the Simulator, there are various macOS utility apps, which let you easily view the Simulator files. I use SimPholders. There's also one called simMagnifier, which lets you veiw (and even edit) Core Data content. That might be worth a look, @GnerphSoft.

Here's your code, unmodified, running on a Mac. SwiftUI works on multiple platforms, and the details of how some styles appear can be platform-dependent. So two styles might look the same on iOS, but could behave differently on macOS.

What is a "TableController"?

When Xcode 13 stable version will be available for public? I would expect this on Monday, when iOS 15 releases. I have upgraded my iPad to iOS 15 RC version and couldn't able to run my application from my Xcode 12.5.1 version to iOS 15 RC now. Correct. • Xcode 12.5.1 cannot be used with iOS 15 • You can use Xcode 13 RC, or wait for the publicly available Xcode 13. • "RC" should be functionally identical to the final Release version (but it is not unknown for there to be an RC2, with further changes).

When you first ran Xcode 13 RC, were you prompted to "Install Additional Components"? ...and did you?