Those were never pictures of the board or the chip. The images are credited to an illustrator. The report itself never mentioned 6-pin. And if you listen to the Risky Business podcast, the chip image is actually a signal coupler sold via Mouser Electronics, that Joe Fitzpatrick sent the journalists a link to when they asked him "what does a signal amplifier or coupler look like".

https://risky.biz/RB517_feature/

https://appleinsider.com/articles/18/10/08/security-research...

Actually, you can check for yourself. It's the first photo result at Mouser if you search for "signal coupler". Seems everyone has been running around trying to find a TDK HHM22137A2 on their Super Micro boards:

https://au.mouser.com/_/?Keyword=signal+coupler