If an app is a client of NSNetServiceBrowser, and attempts to search for services while the local network access permission is not granted for that app, will there be a specific error or notification? Will the app be able to determine the reason why no services were found? Or will this case be undistinguishable, from the app's point of view, from the case where the permission is granted but no services were found on the network?

Is there an API which allows an app to query the state of the local network access permission (i.e. to check whether the user has granted the permission or not)?

Are there any high-level APIs which allow to discover devices on the local network using SSDP, without requiring the multicast entitlement? - https://developer.apple.com/documentation/bundleresources/entitlements/com_apple_developer_networking_multicast

From this - https://developer.apple.com/documentation/bundleresources/entitlements/com_apple_developer_networking_multicast, we understand that if an app implements some form of local network multicast/broadcast, it must have the com.apple.developer.networking.multicast entitlement. But what will happen if the app doesn't have the entitlement? E.g. because the multicast is implemented by a third-party SDK and the app developer is not aware of the entitlement requirements introduced by that dependency? Will this be detected at build time, or during app review, or will multicast just not work at runtime? Or something else? We maintain an SDK which does local network multicast, and wish to understand the implications for our client apps.