[nequo]

Try something that’s unique to one BSD or another. For example, NetBSD supports Lua for kernel scripting[1] and Veriexec[2] for checking the integrity of executables.

[1] https://man.netbsd.org/luactl.8

[2] http://netbsd.org/docs/guide/en/chap-veriexec.html

[jaypatelani]

Also rump kernels