Xcode 13.0 RC 1 was released on 14 Sep 2021 and requires macOS 11.3+.
It can be downloaded from https://download.developer.apple.com/Developer_Tools/Xcode_13_Release_Candidate/Xcode_13_Release_Candidate.xip.
Release notes are located at https://developer.apple.com/documentation/xcode-release-notes/xcode-13-release-notes.
The SDKs it contains are:
- iOS 15.0 (Build 19A339)
- macOS 11.3 (Build 20E214)
- tvOS 15.0 (Build 19J344)
- watchOS 8.0 (Build 19R341)
The compilers it contains are:
- clang 13.0.0 (Build 1300.0.29.3)
- swift 5.5 (Build 1300.0.31.1)