Remarks

EPSG description:

"Information source. This is a brief textual description of the source from which OGP Geodesy Subcommittee has obtained the information. It may include an internet URL current at the time of record population." (OGP Geomatics Guidance Note number 7, part 1, section 5.8.)

Many datum shifts are published in two versions by EPSG, one original transforming to a ground-fixed realization of Wgs84 (like ETRS89, GDA94 or SIRGAS 2000), and one clone transforming to Wgs84. For these, EPSG will usually give the original information source only in the original version, while they give "OGP" as information source in the clone (EPSG is nowadays really the OGP Geomatics Committee). However, just "OGP" is not so informative, so Carmenta has restored the original information source in the cloned datum shifts.