As one of the people responsible for that, the backstory is that at the time very long ago (2008?), it wasn't clear how to handle Unicode text in a cross-distro bugfree way while passing through a Haskell library like XMonad from a Prompt into X11 or the shell or applications, no one had the appetite to make an in-depth study of the various systems to figure out what exactly had to be done to handle ASCII & Unicode in a way that would be safe everywhere, and `encodeString` seemed to sorta work in most cases and be better that what came before. Since the Haskell and other ecosystems have gradually continued evolving (one hopes), it's possible that many Unicode-related issues have since quietly vanished, and XMonad could do something simpler and more correct than it does now; but one would need to investigate thoroughly on a couple systems before one could be sure it was safe to update `spawn` and all downstream users of `encodeString` etc, and no one has been willing to do so to the extent to make a change in the (generally very stable) HEAD. -- gwern https://www.gwern.net