The idea is that you can reset just the config bits. So the bits that keep the JTAG/SWD/ICSP from reading out the flash. So imagine your flash is over here, an

The idea is that you can reset just the config bits. So the bits that keep the JTAG/SWD/ICSP from reading out the flash. So imagine your flash is over here, and your SRAM is over here, and over on this other side is the SFRs and inside those are bits that once set disable the debug interface. Reset just those and you can dump the firmware.