Opaque binary blob
Opaque Binary Blob (or OBB for short; plural: OBBs for blobs) is a term used in Network Engineering and Computer Science to refer to a sizeable piece of data, which looks like binary garbage from outside (by entities which do not know what that blob denotes or carries) but make sense to entities which have access permission to them, and have access functions to them.
Use in Networks
At least one Network Protocol, Advanced Message Queuing Protocol, uses the terminology of OBB.
Use in the Computer Field
Android Operating System-- code named Gingerbread—starting with version 2.3 uses OBBs to refer to multiple files—may be even a file system—in a single blob: A whole file system in a single file.
These OBBs are available through the Storage Manager interface in Android -- Storage Manager in Android.
For example, if there was a map database (map OBB) multiple mobile applications running on Android 2.3 (Gingerbread) can access the (same map) OBB. This eliminates the need to maintain different map data for different, but similar functionality and featured, applications.
Tuxedo (software) "also" uses OBBs to mention C and C++ arrays -- or typed buffers. This probably (input needed from knowledgeable souls) is the oldest reference to OBBs used in a computer system.