Apple Building Developer Center at Apple Park Campus
Schiller did not provide additional detail on the Developer Center, and it has not previously been announced by Apple, so little information is available at this time.
In the past, Apple had Developer Compatibility Labs for Mac OS X developers, and it's possible that the new Developer Center will offer similar functionality. Developer Compatibility Labs offered developers access to Apple facilities in Cupertino, California or Tokyo, Japan to test their software or hardware products with a wide range of Apple devices to ensure compatibility.
The Developer Compatibility Labs, which have since been discontinued, were priced at $99 and supported up to 10 people, with 500 different hardware configurations available.
The new Apple Park Developer Center will presumably allow developers to visit Apple Park to test apps and work with Apple engineers to fix bugs and implement new features. We've asked Apple for more information and will update when we hear back.