As Quinn mentioned, I've been working on swift-book-pdf to create EPUB and PDF editions of The Swift Programming Book. I've brought the Swift Programming Series back to Apple Books, with optimized editions of The Swift Programming Language from Swift 5.8 onward. You can also download PDF and EPUB editions across Swift releases from the Swift Book Archive. Read more here: Swift Book PDF: The Swift Programming Language is back on Apple Books — plus PDF and EPUB archives (forums.swift.org). This project is not published by, endorsed by, or affiliated with Apple Inc. or the Swift.org open source project. See the Acknowledgments chapter in each edition for more details.

You don't need to use the built-in SCM to resolve this issue. Instead, try adding the public key fingerprints to Xcode’s internal fingerprint store in com.apple.dt.Xcode.plist under IDESourceControlModernKnownSSHHostsDefaultsKey. You’ll need a different public key fingerprint for each remote repository service. For example, do the following to add Github's SSH key fingerprint: # Quit Xcode first $ defaults write com.apple.dt.Xcode IDESourceControlModernKnownSSHHostsDefaultsKey -dict \ github.com "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOMqqnkVzrm0SdG6UOoqKLsabgH5C9okWi0dh2l9GKJl" # Confirm the entry was added $ defaults read com.apple.dt.Xcode IDESourceControlModernKnownSSHHostsDefaultsKey { "github.com" = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOMqqnkVzrm0SdG6UOoqKLsabgH5C9okWi0dh2l9GKJl"; } IDESourceControlModernKnownSSHHostsDefaultsKey is stored as a dictionary in com.apple.dt.Xcode.plist. Entries are host -> string, where the string is an OpenSSH known-host style value (<algorithm> <base64-key>), e.g. ssh-ed25519 AAAA....