I serfed googlemap api help section for getLatLng.

The answer to my question was there.
The following is the defintion for the function and description.

getLatLng (addr:string, callback:function)
return: returns nothing
description: Sends a request to Google servers to geocode the specified
address. If the address was successfully located, the
user-specified callback function is invoked with a GLatLng
point. Otherwise, the callback function is given a null point.
In case of ambiguous addresses, only the point for the best
match is passed to the callback function.

So in summary, it is defined by getLatLng function. I hate black box notation but in this case, that is what it is.

Thanks Chris/Lucinda anyway.