NEXTSTEP
NeXTSTEP (also written NeXTstep, NeXTStep, and NEXTSTEP) was the object-oriented, multitasking operating system developed by NeXT Computer to run on its range of proprietary workstation computers, such as the NeXTcube. It was later ported to several other computer architectures.
Available to all SRX running 12.3X48+
Available to all MX running 20.2R1+
Available to all vSRX running 20.3R1+