Enabling ProGuard obfuscation for the release build

/app/build.gradle

android {
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile(‘proguard-android.txt'),
                    'proguard-rules.pro'
        }
    }
    ...
}

With each build, ProGuard outputs the following files: dump.txt mapping.txt seeds.txt usage.txt app/build/outputs/mapping/release/