MIUI System Launcher ALPHA-4.21.0.2300-09101220 by Xiaomi Inc. https://www.apkmirror.com/apk/xiaomi-inc/miui-launcher/miui-launcher-alpha-4-21-0-2300-09101220-release/
APKMirror
MIUI System Launcher ALPHA-4.21.0.2300-09101220 APK Download by Xiaomi Inc. - APKMirror