I do not know how that article covered so much background on GNU hURD and the quest for a micro-kernel UNIX without mentioning Redox OS.
Redox is also micro-kernel based POSIX compatible operating system (UNIX compatible). So quite like the GNU project and HURD in that sense.
Redox is younger, 10 years old instead of 30, and more “modern” (eg. written in Rust). It can be seen as a GNU competitor as it does not rely on the GNU C library or utilities.