ok
then PLEASE look in all files of sdk/as/bindings/*.cpp;*.h ;-)
seriously, take a look in these files and try to understand it,
when you have a specific problem with the usage of these commands, then post it here,
if you look specifically for the GetBuiltinActiveEditor() method,
you see in the scriptbindings.cpp the following registering for it
engine->RegisterObjectMethod("EditorManagerClass", "Editor@ GetBuiltinActiveEditor()", asMETHOD(EditorManager, GetBuiltinActiveEditor), asCALL_THISCALL);
as far as i understand it, the @ is obviously part of the declared typename,
used to tell the as-engine, that a custom data object of type "Editor@" is used as returnvalue.
therefore we declare a Editor@ type in order to match the definition for the method GetBuiltinActiveEditor()
it is nothing fancy, PLEASE just take a moment to look in the files i told you
(and i got told to look into from Yiannis ;-) )
how it works.