CPackIFW: what is "@ApplicationsDir@"

The CPackIFW help page says about the variable CPACK_IFW_TARGET_DIRECTORY: "Default target directory for installation. By default used @ApplicationsDir@/CPACK_PACKAGE_INSTALL_DIRECTORY"

What kind of macro is this @ApplicationsDir@? Where is it defined, how does it expand by default, how can it be modified?

It seems to be an IFW pre-defined variable according to this report. I see documentation for it on this IFW doc page.

Thanks, Ben. Your answer is part of