Calling

QLocale().uiLanguages()

doesn't work as expected on Android 6.x where is always return an empty list. The same bug also happens when using the QML version:

Qt.locale().uiLanguages

The main effect is that calling the load method of a QTranslator passing a QLocale() as first argument simply doesn't work, and apps are not translated.

I attach a simple test app reproducing the issue.

Result on x86 Android emulator with android 6.0

Same apk on Android 9.0, works properly.