I'm counting different editions of POSIX-compliant shell languages (e.g. ksh93, zsh, bash, [t]csh) as different, as well as massively different editions of DOS

I'm counting different editions of POSIX-compliant shell languages (e.g. ksh93, zsh, bash, [t]csh) as different, as well as massively different editions of DOS (freeDOS, MSDOS). Hence the approximating tilde on "~12". Reasonable minds may consider there to be many fewer, or many more, compatible interpreters. EDIT: There also appear to be multiple compatible JavaScript interpreters--browser V8 (though not Node, oddly--it's detected as generic; I may send a PR sometime), SpiderMonkey, and older IE. I'm no expert on JS runtimes, though, so the differing results I'm observing may be due to something else.