25 years ago, I configured GNOME to run a BeOS-like tabbed window manager. On a sun workstation.
But that's not what this is. Or not only:
Nexus Kernel Bridge
Nexus is Vitruvian's custom Linux kernel subsystem that brings BeOS-style node monitoring, device tracking, and messaging to Linux — making it possible to run Haiku applications on a standard Linux kernel.
It claims to run apps from Haiku, the current open-source implementation of a modern BeOS.
Looks like this is a thin translation layer for BeOS/Haiku syscalls. I wonder why they aren't relying on Syscall User Dispatch https://docs.kernel.org/6.19/admin-guide/syscall-user-dispat... which would enable them to put this compatibility layer in user space. It's already being used by recent Wine versions.