@jimmy@VIPPER Not the greatest link (this guy actually believes that copying software is theft and that translating a program line-by-line to Rust doesn't make a derivative work) but it does at least does show that the code of the RT kernel certainly was not copy-pasted.
It seems possible that they looked at the kernel design and implemented a similar structure (which was later changed to be different too), but who cares, as they wrote free software and respected the users freedom and didn't write proprietary software.
marcan is the same guy behind Asahi Linux and a also someone that has displayed gyspy tendencies for decades, being a fucking nuisance and picking fights on several game console hacking scenes on the side of corporate scumbags.