Thanks for the helpful note.
Perhaps I need to get to coding my own module installer. I appreciate that "everything, everywhere, must support i18n" is noble, but I think it's pretty ugly to encode filenames in the install tree on all systems, because there exist systems that can't represent some names of some modules. If I'd asked zef to install a package with a name in a script appropriate to a language I don't know, and which my filesystem didn't support, I'd expect ugliness. But Readline represents fine in US-ASCII.