Hurd is actually not Unix nor Linux. But more superior says. Where Plan9 and Linux are in the range of Unix/Linux. eCos and FreeRTOS is also completely not unix/linux.
What is the main differences between Hurd and FreeRTOS/eCos and General Unix/Linux?
Can i name FreeRTOS or eCos tree as Hurd family? As those OS are not considered to be Linux nor Unix.