Like previous flows,
fixed.xsa can be used for many purposes like application development running on Petalinux/Yocto, XRT, or bare-metal flows. Later, generate the xcilbin using the v++ package command:
v++ -p -t hw --platform ./vivado_impl/flat_fixed.xsa ./aie/libadf.a -o flat_hw.xclbin
This step will generate the .xclbin without having any software details like rootfs etc,. To run the design on hardware, you need to add the software details while packaging. Refer to the Building and Packaging section in UG1393.