Hey... what's wrong with Tcl? Whenever I have a shell script and want to tack on a "GUI", Tcl/Tk is the most time-economical one for me. I am happy that it is still around, and that it works on most platforms (of course not mobiles... but I "wish").
If any maintainers are reading: putting it in the F-Droid store would improve visibility / discoverability.