XAPK -> APK ez

mv app.xapk app.zip

mkdir carpetaXAPK

cd carpetaXAPK

unzip ../app.zip

wget https://github.com/REAndroid/APKEditor/releases/download/V1.4.1/APKEditor-1.4.1.jar -O APKEditor.jar

java -jar APKEditor.jar m -i carpetaXAPK -o app.apk