This app doesn't collect any data about you or your device. It only locally saves data that is needed for normal operation, such as the last listened track, playlist membership, preference of literal or final translation, and similar. This is saved on your device and never uploaded anywhere.
Source code can be seen at https://github.com/mg94c18/gonzales (for Android) and at https://github.com/mg94c18/gonzales-ios (for iOS).
Author: mg94c18, and here is email too, although nobody really uses it: yckopo@gmail.com