如何解压我在Android 8.1 rom（aosp Based）中找到的system.new.dat.br文件

I recently downloaded a aosp based rom from xda for my Xiaomi redmi note 3 pro(kenzo) device. It's name is "Pixel experience android 8.1". when extract the rom zip file, there is a file name "system.new.dat.br" , I want to extract it or unpack. but i can't do it. please can any one help me about this how to unpack the new type system. I recently downloaded a aosp based rom from xda