chm files are basically html files packed into an archive.

unpacking them should be possible, but

archmage file.chm output

“Segmentation” faulted.

lsb_release -a; # tested on
No LSB modules are available.
Description:	Debian GNU/Linux 10 (buster)

su - root
apt update
apt install xchm

then in caja (or other file explorer) r-click-the-file-> open with xchm

even comes with cross os support! (lin, win, osx)

the GPL licenced src is here:

the author does not have any access anymore to: (someone else restored the page, might be scam!)