@CZvacko As for translation, you can translate via the POEditor
https://poeditor.com/join/project/ynjQmwSsGh
And if you want to test a translation, then you can convert the PO-format to JSON-format (see the build scripts in ./bin/i18n/) and put the JSON-file in the JAR-file (it’s just a ZIP-archive, location frontend_client/app/locale/)