maxv cares deeply for netbsd's security and has found multiple bugs in syscall emulation layers. So he took part in creating tools that mechanize the work of finding them, KASLR, KLEAK. But they need to run the code to find bugs.
Most likely, COMPAT_ULTRIX and COMPAT_OSF1 have the same type of bugs that we have seen in compatibility layers elsewhere. Is it worth his time to test them? This means: - Finding binaries to run - Setting up an emulator* - Porting KLEAK/KASLR to the architecture that can run COMPAT_ULTRIX etc. given how old it is, it sounds very likely it has bitrotted. apparently COMPAT_ULTRIX hasn't, so we can keep it, OK. Removing 1 out of 2 suggestions is still a small victory. Pruning code is healthy and I'm glad we can have a reasonable discussion about it where users can mention they find the code useful. * Bonus points that netbsd/alpha doesn't run in any emulator AFAIK, so actually you would get stuck if you tried.