Thanks for the link, Annie!
Three part Pyro developers are not uncommon. The three way split was made in an attempt to improve developer shelf life by keeping the alkali (carbonate) and most of the preservative (sulfite) as separate solutions. Michael Smith's ABC Pyro formulation is a slight variation on the Agfa-Ansco-GAF 45 formula.
Kodak D7 is a three part Pyro/Metol formulation.
Agfa-Ansco-GAF 125 is the only formulation that is consistantly listed by Agfa-Ansco-GAF as suitable for development of both Film and Paper. Agfa-Ansco-GAF 125 is an MQ formulation that is virtually identical to Kodak D-72 (i.e. Dektol).