Xcode 10.0 Beta 2 was released on 19 Jun 2018 and requires macOS 10.13.4+.
It can be downloaded from https://download.developer.apple.com/Developer_Tools/Xcode_10_Beta_2/Xcode_10_Beta_2.xip.
Release notes are located at https://download.developer.apple.com/Developer_Tools/Xcode_10_Beta_2/Xcode_10_Beta_2_Release_Notes.pdf.
The SDKs it contains are:
- iOS 12.0 (Build 16A5308d)
- macOS 10.14 (Build 18A314f)
- tvOS 12.0 (Build 16J5303d)
- watchOS 5.0 (Build 16R5303d)
The compilers it contains are:
- clang 10.0.0 (Build 1000.10.25.5)
- swift 4.2 (Build 1000.0.16.9)