Install xchm by entering the following commands in the terminal:
sudo apt update sudo apt install xchm
Description:
Compiled HTML Help (CHM) file viewer for X
xCHM is a viewer for Compiled HTML Help (CHM) files. It can show the contents tree if one is available, print the current page and do the usual history stunts. It allows one to change fonts and search for text in all the pages of the file, or in the page's titles. . xCHM does not support JavaScript in books.
Homepage: http://xchm.sourceforge.net/
Version: 2:1.23-2build2
Section: universe/x11