Figuring out what type of error in unboxed in SwiftyDropbox

I'm trying to understand how to catch and parse errors from the swifty dropbox SDK, specifically route errors. Apologies if this is a simple question, I'm new to Swift!

In the examples that I've seen (for example here), a route error is unboxed and then cast to a specific error type like this:

case .routeError(let boxed, let requestId, nil, nil):
        switch boxed.unboxed as Files.ListFolderError {
          case .path(let lookupError):
...

What I'm struggling to understand is how do you know what type boxed.unboxed should be (in this case it was files.ListFolderError)?

For example, for the uploadSessionStartBatch route, I have the following code - what kind of route error does uploadSessionStartBatch return? How do I find this out? I'm trying to cast it to a type which I can parse to detect if the user is out of space.

do {
    let uploadSessionStartBatchResult = try await client.files.uploadSessionStartBatch(
                            numSessions: UInt64(filePaths.count), sessionType: .concurrent).response()
}
catch {
     switch error as? CallError<Any> {
         case .routeError(let error, let userMessage, let errorSummary, let requestId):
              switch error.unboxed as Files.???? {
                   // e.g. catch insufficient space error
              }
                            
     }
}

Thanks so much!