Is there some connection to CarbonFive[0], the consultancy, or did they just.... um... completely duplicate their logo by accident or something?
SiFive's actually fits this design more even though it came out later. They don't need the added shape at the bottom and the embedded character can be seen as either "s" or "5" while the carbon 5 one needed the extra bit at the bottom and is a bit harder to see the "5".