Asked in the forum:

https://moodle.org/mod/forum/discuss.php?d=357985

The Cordova File plugin allows storing the files in the external storage:

cordova.file.externalDataDirectory - Where to put app-specific data files on external storage. (Android)

We need to decide how to approach this. Should it be configurable? If so, we should move all the existing files when the user changes the setting.