app/src/main/res/xml/locales_config.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- Notice, when adding a new locale, this list must be
kept synchronised with the one defined in build.gradle (app).
Aka. then resourceConfigurations -->
<locale-config xmlns:android="http://schemas.android.com/apk/res/android">
<locale android:name="en" />
<!-- <locale android:name="en_US" /> -->
</locale-config>