The current[1] distribution comes with a hn clone, that as far as I know, is mostly equivalent to the code that used to power hn at some point in the not too distant past.

[1] current might not be the best name for it, but as far as I can tell it a) works, b) has been ported to Racket (as opposed to being trapped on some ancient version of PLT Scheme), and c) is maintained (ish): https://github.com/arclanguage/anarki