A VOB is a repository for data (versioned artifacts such as files and directories) and metadata (branches, labels, event records, and so on). Some metadata types are stored as VOB objects; other metadata is stored as records or annotations attached to these objects.
Some VOB datatypes are created automatically by Rational® ClearCase® commands. Others must be created explicitly by users or (more often) administrators. You must use commands such as cleartool describe and various Rational ClearCase GUIs to access VOB metadata.