@Paul:
Can you please include the translations in your build, too? It's missing from the Qt5 and there is an issue open for it.
I can look at this - do you have any idea how these are enabled on other platforms?
TBH, I have no clue.
All I know is, that it is its own module QtTranslations, which BWW hadn't cloned, so I have to bundle the translations with FeatherPad and FeatherNote, which is less than ideal.
It also concerns the shortcuts and its translations. Without it and any other locale than en, shortcuts can fail to be recognized. I had this issue with my de locale. Eg. CTRL will be translated to STRG in German and the CTRL shortcuts will not work.