Here is the format of the DATA for a TRef object in Release 3.02.06.
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0->1 Version = Version of TObject Class (base class of TRef)
2->5 fUniqueID = Unique ID of referenced object. Typically, every referenced
| object has an ID that is a positive integer set to a counter
| of the number of referenced objects in the file, beginning at 1.
| fUniqueID in the TRef object matches fUniqueID in the
| referenced object.
6->9 fBits = A 32 bit mask containing status bits for the TRef object.
| The bits relevant to ROOTIO are:
| 0x00000008 - Other objects may need to be deleted when this one is.
| 0x00000010 - Object is referenced by pointer to persistent object.
| 0x01000000 - Object is on Heap.
| 0x02000000 - Object has not been deleted.
10->11 pidf = An identifier of the TProcessID record for the process that wrote the
| referenced object. This identifier is an unsigned short. The relevant
| record has a name that is the string "ProcessID" concatenated with the
| ASCII decimal representation of "pidf" (no leading zeros).
| 0 is a valid pidf.
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