image (1.0) below is Dynamo open with a open Python node typical template with an overlay of the ProtoGeometry.dll file opened
image (1.1) below is ProtoGeometry.dll file scrolled down to show the area from which matched the Dynamo Geometry menu.
clr.AddReference('ProtoGeometry')
from Autodesk.DesignScript.Geometry import * 
  • C:\Program Files\Dynamo\Dynamo Core\2\ProtoGeometry.dll
  • Decomplie
  • Open

import * = Importing star (asterisk, everything in a library)

DataEnteringNode = IN[0] = just what it says

Out = point.add = just what it says. Looking to image (1.1) near the top of the list you will find Add(Vector vector ToAdd):Point. This is where this method (what I would call a command) is coming from.