Large files are split to bypass the upload limits of hosting services or to fit onto smaller storage media like FAT32 drives.
In technical and gaming communities, "OB" often refers to files. These are large expansion files used by the Android operating system to store assets—such as high-definition graphics, audio, and map data—that exceed the standard APK installation limit. Download (O B) part3 rar
Developers use OBB files to deliver heavy content separately from the application's executable code. Large files are split to bypass the upload