This is a military chip. It's used in military applications. I'm not saying that the original article didn't use this to sensationalise 'We JTAG-fuzzed a chip and found an AES key', but to deny that the chip is used in the military is inaccurate.

Good call on the Chinese front, we don't know who generated the key material to block the JTAG.

Incidentally on z/OS systems things that open the system up to external access are sometimes referred to as backdoors, which is what this is. It's a way of accessing the chip, nothing more.