Latex Macros from decker.yaml

I want to define a latex macro for a decker project.

When defining mathMacros in the decker.yaml, the predefined macros in the deck.html are not assigned. (Line 554)

But if mathMacros is a list or a dictionary (which it has to be to copy the preexisting macros), the resulting window.Reveal.getConfig().math.macros is true instead of an object {...}. Thus I am unable to define any macros with it.

Is this normal behaviour? If so, how can I add latex macros to a project without rewriting the template code?

Best regards, Matthias