Signal-Android/contacts/app/src/main/res/xml/authenticator.xml

<account-authenticator xmlns:android="http://schemas.android.com/apk/res/android"
                       android:accountType="org.signal.contactstest"
                       android:icon="@mipmap/ic_launcher"
                       android:smallIcon="@mipmap/ic_launcher"
                       android:label="@string/app_name"/>