-``an exchangeable file format for bitstream assembler``: Software engineers can use the raw bitstream to build a bitstream assembler which organize the bitstream in the loadable formate to FPGA chips.
-``creation of artificial bitstream``: Test engineers can craft artificial bitstreams to test each element of the FPGA fabric, which is typically not synthesizable by VPR. Use the ``--read_file`` option to load the artifical bitsteam to OpenFPGA (see details in :ref:`openfpga_bitstream_commands`).