I know it's way too late, but we just hit this problem. Safari is stripping path and query from url before it passes to FindProxyForURL. So basically Safari passes domain name with protocol instead of url with path and query - instead of "https://forums.developer.apple.com/forums/thread/719939" Safari use "https://forums.developer.apple.com/" as url in FindProxyForURL Same with Chrome (you can't change the behaviour) and Firefox (you can override the default behaviour by setting an internal flag).

You'll need to implement Broadcast extension with RPBroadcastSampleHandler subclass.