It used to return some readable derivative of the device name in .local domain. Since device name is not accessible anymore (without special entitlement) we used gethostname() as a "hint" reference in logs and across web UIl where long lists of enrolled devices are listed.

Formally "localhost" can be valid, however logically it's as meaningless as would any API returning fixed string would be. Effectively gethostname() cease to exist as a function and becomes an equivalent of string "localhost". In any case would be nice if you could confirm the change since it's not mentioned in Release Notes, as it seems.

Before it was useful, since it produced an output which could be easily recognized and narrowed out of a long list of other devices. Now it's truly meaningless - perfection achieved. Fun discussion to have in front of a fireplace with a glass of good scotch, but irrelevant to millions of user faced with amazing and very readable "localhost" or UUIDs a-la "486398F2-76EC-475A-8549-5219672CBF01" instead of awful "Joe's iPhone" or "joes-iphone.local" as it used to be. I've filed FB12407865.

I also noticed that custom URL scheme and ASWebAuthenticationSession combo doesn't have this Open button issue, but was worried that this is some kind of omission/bug and it may get fixed later. After your explanation it looks like expected behavior and this helps a lot. Essentially applinks purpose is for direct app/browser integration and not meant to work with ASWebAuthenticationSession API. Thank you!

Looks like a bug to me - Editor menu has both Inline and Side By Side comparisons available, but switching between them has no effect.

Filed FB13048984. Thank you!