I remember the time when ArchiFM was product of Graphisoft. It was called Graphisoft ArchiFM. It was the same ArchiCAD 6.5 with Add-Ons. Later this development probably went to the company called VintoCon.
Today VintoCon web-site is not available and it's only possible to open ProFM help-desk web-site.
Very possible that this product has been discontinued.
As I understand - all subtypes are coming from old time - when ArchiFM was real product (that requested libraries too). Since that time we have FM_ variables. Probably nobody did revision of ArchiCAD library to remove FM_ from list of variables or replace it with CoBie. By another hand most of the library elements on NBS web-site do have CoBie parameters (to support UK BIM standard).
Finally it's not so important what prefix got GDL parameters - as soon as this is internal ArchiCAD standard. In any case GDL parameters must be mapped to IFC parameters - as IFC is a file, that must support CoBie standard.
There was a time, when Graphosft tried to push GDL technology as international standard for AEC libraries - was created internet browser plug-in and plug-in for AutoCAD, but looks like Ravit families won this war. I personally would be absolutely happy if GDL would be widely used in AEC programs - like Revit, Sketchup, Vectorworks, Tekla etc. Then the whole structure of variables would be more standardised.
