In the Insight for DB2 R12 System Reference Guide, Chapter 7, section Historical Backups of Performance Data, it talks about the new unload process for linear vsam files: IDUNLJCL.
In Chapter 8: Archiving DB2 Performance Data it references the old process IDB2UNLD and shows its use in the graphics. Is this a contradiction?
This is not a contradiction. If you take a look at the program names of R12 and R11.5 IDB2UNLD you'll notice that they are different:
R11.5 IDB2UNLD uses EXEC PGM=IDB2UNLD whereas R12 IDB2UNLD uses the new utility created for reading the linear dataset EXEC PGM=IDB2UIFI.
The references to IDUNLJCL and IDB2UNLD are to sample JCL members in the SOURCE dataset. Both members use the same program, IDB2UIFI.