At the moment @mstdnuser and I just suppose that @dean wants to confirm which non-free firmware he needs on his XPS laptop with # dmesg | grep -i firmware or by reading the # lshw output, but you are direct and absolutely right: none needs to understand (worthless) why this Dell laptop needs firmware-iwlwifi, initramfs-tools and probably firmware-misc-nonfree as well (workable even without “enabling the Debian non-free repo”).