You can use https://github.com/HoloISO/holoiso though

Or just launch Steam with the command line argument that gives it the Steam Deck UI

You can find the packages here with at least some of the sources here https://steamdeck-packages.steamos.cloud/archlinux-mirror/

Wouldn’t the GPL require them to publish SteamOS 3? At least the source code, if not the ISO.

Like with Android, I think only parts of the software that's GPL licensed, like the Linux kernel. It looks like this repo keeps a list of the license violations: https://gitlab.com/evlaV/holo-PKGBUILD#third-party-packagesr...

Anyone knows what evlaV are labelling as "obfuscated"? I doubt valve released actually obfuscated source code. Are they complaining that the source is available as src.tar.gz containing patches+original source (more or less like Arch manages it) instead of git repository with history?