Apple、デベロッパー向けに macOS Mojave 10.14 beta 6 (18A353d )、iOS 12 beta 6 (16A5345f)、watchOS 5 beta 6 (16R5340g)、tvOS 12 beta 6 (16J5340e) を配布開始
https://developer.apple.com/news/releases/