Gadgetbridge/app/src/main/assets/logback.xml

<configuration debug="true">

    <appender name="STDOUT" class="ch.qos.logback.classic.android.LogcatAppender">
        <!-- encoders are  by default assigned the type
             ch.qos.logback.classic.encoder.PatternLayoutEncoder -->
        <encoder>
            <pattern>%msg</pattern>
        </encoder>
    </appender>

    <root level="DEBUG">
        <appender-ref ref="STDOUT" />
        <!-- The FILE appender is added programmatically by nodomain.freeyourgadget.gadgetbridge.Logging -->
    </root>
</configuration>