APK, XAPK, and OBB Files and ModJoy APK: A Guide for Low-Storage Android Phones

https://greengamenest.readspirex.com/posts/misleading-redirects-and-mod-joy-what-mobile-gamers-should-know

On a phone with little free space, every download and update needs a little more planning. APK, XAPK, and OBB labels describe different ways Android apps and large game assets may be packaged or delivered