Since the details of "rf-balance" are written directly in English in "settings.lua," the game will display in English even if you are playing in a different language.
This is a difficult problem to notice when playing in English.
To enable multilingual support, avoid using "localized_description" in "settings.lua" to describe English directly.

Good catch, I must have written that back when I was still figuring out how localized descriptions worked. Should be fixed to use values from the locale.cfg (although these setting descriptions don't currently exist in other languages anyways), as of v9.0.33