The revised text with 3–4 is as follows: What is an APK file? -------------------. The Android operating system distributes and installs mobile applications usieasy jackpot vegas slotsng a file format called an APK, which stands for Android Package Kit. It is essentially a package that includes every element required for an application to function on an Android device. This comprises the manifest file, resources, assets, and program code that specify the structure and permissions of the application.