A file with .xapk extension is a compressed package file that is used to install Android apps on mobile devices. It is a container file format that incorporates APK and additional associated files required for the installation. The other associated file is an OBB file that stores additional files such as graphics, media files, and app data that are required to keep the application running. XAPK files are not supported by Google Play and are used for distributing on third-party Android app download websites only. These can be installed to an Android device using XAPK Installer.
XAPK File Format
XAPK files are compresed using the standard ZIP file format. These can be extracted using a standard compression/decompression software such as WinZIP. Once the XAPK file is extracted to the disc, it contains the following files in folder.
APK - Standard installation file for installing the application on Android devices
OBB - Additional file that contains relevant resource files