MarsSeed [1] filed a deletion request for gnochm [2]:

I suggest to delete this Gtk2 and Python 2 based Microsoft Help File (CHM) viewer (GUI app). Project stopped in 2007 (15 years ago).

Last user comments here are from 2015 and it seems the application was not able to function at that point in time.

There are good, working applications/libraries to view and/or import/convert Microsoft CHM files. So this defunct one is not needed and not worth keeping in my opinion.

[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/gnochm/