Xcode 12.0 Beta 1 was released on 22 Jun 2020 and requires macOS 10.15.4+.
It can be downloaded from https://download.developer.apple.com/Developer_Tools/Xcode_12_beta/Xcode_12_beta.xip.
Release notes are located at https://developer.apple.com/documentation/xcode-release-notes/xcode-12-beta-release-notes.
The SDKs it contains are:
- iOS 14.0 (Build 18A5301v)
- macOS 10.16 (Build 20A4299v)
- tvOS 14.0 (Build 18J5313t)
- watchOS 7.0 (Build 18R5310a)
The compilers it contains are:
- clang 12.0.0 (Build 1200.0.22.7)
- swift 5.3 (Build 1200.0.16.9)