Download smog
One AppImage for x86_64 Linux. No installer, no root, no account. It finds your Steam library and Proton versions on its own.
Builds
The launcher is coming soon.
The first AppImage is still being tested on real hardware before it goes up. Until then you can browse the catalog, and every entry page shows exactly what the launcher will install and from where.
Install and run
Download the file, make it executable and run it. You can keep it anywhere; your home folder or ~/Applications is a good spot.
$ chmod +x smog-x86_64.AppImage
$ ./smog-x86_64.AppImage
If it will not start and mentions FUSE, install your distribution's fuse2 or libfuse2 package, or run it with --appimage-extract-and-run.
Verify the download
Compare the file's SHA-256 with the one listed above. The two must match exactly.
$ sha256sum smog-x86_64.AppImage
After that, smog updates itself. Updates are signed, and the launcher refuses any update whose signature does not match the minisign key compiled into it. The catalog of games is signed the same way, with a separate key; you can check it by hand:
$ curl -s --remote-name-all https://smog.games/catalog/catalog.json{,.minisig} https://smog.games/catalog/smog-catalog.pub
$ minisign -Vm catalog.json -p smog-catalog.pub