i don't understand either
footprints are component information for mounting to a printed wiring board
you need the pin positions, pad sizes for traces and you need an outline to
avoid component crashes.
the square flange layout is for mounting to a chassis, so you know the hole positions and
diameters and is usually found in a different part of connector data sheets
that is, where the shell and mounting information is, instead of where the insert information is
whatever it is you're looking for, its there