The inclusion of .com as a literal part of the filename (not the TLD) is highly irregular.
In the Android file system, OBB files are used to store large game assets that exceed the standard APK size limit. For a complex title like Half-Life 2: Episode Two , the game is typically split into a "main" OBB and a "patch" OBB: patch.32.com.nvidia.valvesoftware.halflife2eps.obb