Today Apple released iOS 10.3 and watchOS 3.2, new releases of the operating system which include the Apple File System. Apple revealed (APFS) at last year's World Wide Developer Conference (WWDC). Unusually, Apple does not mention APFS in the list of features in iOS 10.3.
Today Jonathan Zdziarski announced on his blog
"I’m pleased to announce that I’ve accepted a position with Apple’s Security Engineering and Architecture team, and am very excited to be working with a group of like minded individuals so passionate about protecting the security and privacy of others.