This has the advantage of executing all your shell mcguffins too, so PYTHON4_LC_COLOR=Europe/Orange is set for the entire desktop session, not just the shells you launch from your desktop environment.

(By the way, exec is a fundamental Unix syscall of interest in that it replaces the current process’s code with new code. Your logout call will never run. The exec is the last thing zsh does before being replaced by sway.)

(What if sway doesn't exist?)

Then you probably don't want the 'logout' there anyway, so you can get a shell and see the output that says why it didn't run.

That’s a good point but I think the original intention was clearly “run sway until it’s done, then logout.”

Also if sway dies not exist just change to tty2 e.g. and log in there. This will not Start sway there.

logout is unreachable here because the previous command is exec