Kchmviewer is a free, open-source CHM (aka MS HTML help) and EPUB viewer
written in C++ for Unix, Mac and Windows systems. Unlike most existing
CHM viewers for Unix, it uses Trolltech Qt widget library, and could
optionally be compiled for better KDE integration. It does not require
KDE, but may be compiled with KDE widget support. Since version 5.0 it
uses the Webkit API to show the content. This script builds Qt-only
version.

The main advantage of kchmviewer is the best support for non-English
languages. Unlike other viewers, kchmviewer in most cases is able to
correctly detect the chm file encoding and show it. It correctly shows
the index and table of context in Russian, Spanish, Romanian, Korean,
Chinese and Arabic help files, and with new search engine is able to
search in any chm file no matter what language it is written.

kchmviewer is written by George Yunaev, and is licensed under GNU
General Public License version 3. It uses chmlib to handle the CHM
files, and some ideas from xchm.