ExtensionFoundation on iOS 26

Hi, I'm trying to add an extension to my app on iOS 26. I've followed the instructions on https://developer.apple.com/documentation/extensionfoundation/adding-support-for-app-extensions-to-your-app

and made it as far as being able to launch the extension:

let monitor = try await AppExtensionPoint.Monitor(appExtensionPoint: .localWebServerExtension)
currentIdentity = monitor.identities.first
if let currentIdentity = currentIdentity {
    let myConfig = AppExtensionProcess.Configuration(appExtensionIdentity: currentIdentity, onInterruption: { NSLog("extension was terminated") })
    myProcess = try await AppExtensionProcess(configuration: myConfig)
     myConnection = try myProcess?.makeXPCConnection()
}

None of these calls throw, and when I examine myProcess from inside that code, it seems to be normal (there's a pid, for example).

Yet the code inside my extension seems to not be executed: breakpoints are not triggered, NSLog() calls do not appear on the console. The onInterruption() callback is also not triggered, or at least it does not appear on the console either.

I've probably missed something obvious, but what could it be?