This directory was added when the sim::IDE class version changed from 11 to 12. Due to an error in ROOT (discovered in version 6.22/08, and fixed in version 6.XY/UV), the streamer information for sim::IDE was not stored in any art/ROOT file that contained a nested collection of sim::IDE objects. ROOT is therefore not able to ensure backwards-compatibility for the sim::IDE class, even though an IO read rule exists.

To work around this limitation, the 'simIDE_streamer_info.root' file in this directory was generated with the necessary sim::IDE streamer information. Backwards compatibility is restored by loading this file whenever the lardataobj::Simulation dictionary library is loaded.

N.B. ROOT files are not generally permitted in LArSoft repositories. An exception has been made for this case so that backwards compatibility could be restored.