You can assign a name to an element path to capture the element content in a DITA2Go user variable of that name.
To map an element path to a user variable:
[VariableMaps] ; element path = name to use for variable with element content, ; or None (variables are ignored, except booktitle and booktitlealt) ; default is the element name itself elementpath = varname
[VariableMaps] mainbooktitle/* = BookTitle
The user variable is then available for use in DITA2Go macros. This assignment applies to any element, regardless of the properties set for the element in [ElementTypes]. How many variables you get depends on how many instances of the element path occur in your document. For example, if you set:
[VariableMaps] title/* = MainTitle
you will get a variable $$MainTitle[index] for every use of title in your document. If you change the setting to:
[VariableMaps] title/map/1 = MainTitle
you will get just one variable, $$MainTitle. How specific you make the path determines how many matches you get.
When elementpath=None (or No), user variables are not created for that particular element path.
The DITA2Go distribution includes the following setting in system configuration file %OMSYSHOME%\d2g\configs\d2g_config.ini:
[VariableMaps] * = None
If you omit all settings in [VariableMaps], this what you get. In this case the only user variables DITA2Go recognizes are for booktitle and booktitlealt, which are handled differently.