What is libclasifier_jni.so in android's apk?

My android apk is around 22MB, even when i have not used anything heavy. After analyzing the apk file i found a directory "lib" which contains a file name "libclasifier_jni.so" for different architectures, I am not sure where it is coming from. below is screenshot for same

Could you please tell me what i'm missing here?

Below is build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 27
    defaultConfig {
        applicationId "com.pixyfisocial"
        minSdkVersion 15
        targetSdkVersion 27
        versionCode 24
        versionName '5.0.0'
        multiDexEnabled true
        testApplicationId "com.pixyfisocial.screens.presenters"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    lintOptions {
        abortOnError false
    }
    packagingOptions {
        exclude 'META-INF/DEPENDENCIES'
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/license.txt'
        exclude 'META-INF/NOTICE'
        exclude 'META-INF/NOTICE.txt'
        exclude 'META-INF/notice.txt'
        exclude 'META-INF/ASL2.0'
    }
    productFlavors {
    }
}

configurations {
    all {
        exclude module: 'json'
        exclude module: 'commons-logging'
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    testImplementation 'junit:junit:4.12'
    testCompile 'org.powermock:powermock-api-mockito2:1.7.4'
    // https://mvnrepository.com/artifact/org.powermock/powermock-module-junit4
    testCompile 'org.powermock:powermock-module-junit4:1.7.4'
    // https://mvnrepository.com/artifact/org.mockito/mockito-core
    testCompile 'org.mockito:mockito-core:2.8.9'
    implementation 'de.hdodenhof:circleimageview:2.2.0'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    compile 'com.android.support:appcompat-v7:27.1.1'
    compile 'com.android.support:recyclerview-v7:27.1.1'
    compile 'com.android.support:cardview-v7:27.1.1'
    compile 'com.android.support:design:27.1.1'
    implementation 'com.facebook.android:facebook-android-sdk:4.33.0'
    compile 'com.squareup.picasso:picasso:2.5.2'
    compile 'com.github.clans:fab:1.6.2'
    compile 'com.theartofdev.edmodo:android-image-cropper:2.7.+'
    implementation 'com.google.firebase:firebase-core:16.0.0'
    implementation 'com.google.firebase:firebase-messaging:17.1.0'
    compile 'com.facebook.android:account-kit-sdk:4.+'
    compile 'com.android.support:support-v4:27.1.1'
    compile 'com.google.code.gson:gson:2.8.2'
    compile 'com.google.firebase:firebase-appindexing:15.0.1'
    compile 'com.google.firebase:firebase-auth:16.0.1'
    compile 'com.google.android.gms:play-services-auth:15.0.1'
    compile 'com.google.firebase:firebase-invites:16.0.0'
    compile 'com.android.support:customtabs:27.1.1'
    compile 'com.google.firebase:firebase-ml-vision:16.0.0'
    compile 'com.google.firebase:firebase-ml-vision-image-label-model:15.0.0'
    compile 'com.github.greenfrvr:hashtag-view:1.3.1'
    implementation 'com.android.support.constraint:constraint-layout:1.1.1'
    implementation project(':pixyfi-data')
    implementation project(':pixyfi-services')
    implementation project(':utility')
}
apply plugin: 'com.google.gms.google-services'

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