Version III of the ENDF/B data file was released in late 1972. There was no formal documentation of the formats and procedures for this version of ENDF prepared and published. For the first time, the "standard" cross sections for neutron-induced reactions were identified. A special purpose "Standard Library" was created and sent to the IAEA for worldwide distribution. A special purpose library for Dosimetry cross sections was created. New fission product cross sections were added to improve calculations of decay heat.
-- Taken from the ENDF/B-VII format manual, Appendix I "Historic Perspective", By Norman Holden.