As far as I know, all the dialogues and scenes are inkcpp. News and mail on a smartphone are like json or just plain text files. But the user interface was in the OptimizedTranslation format from Godot (*.translation files), where the developers decided to save a few kilobytes, which is why it is impossible to restore the original key:value pairs (almost impossible, most likely they can be restored by iterating through all existing lines in the project).