What is a easy way to view texi files?

Install texi2html to convert Texinfo files to HTML:

sudo apt-get install texi2html

Man page of texi2html:

SYNOPSIS

   texi2html [options] file

DESCRIPTION

   Texi2html  converts  the  given Texinfo file to a set of HTML files. It
   tries to handle most of the  Texinfo  commands.  It  creates  hypertext
   links for cross-references, footnotes...

   Texi2html  may furthermore use latex2html to generate HTML (code and/or
   images) for @math and @iftex tags (see the --l2h option).

   Texi2html creates several files depending on the contents of  the  Tex‐
   info file and on the chosen options (see FILES).

   The  HTML  files created by texi2html are in general closer to TeX than
   to Info. Using init files (see the --init-file option), other styles or
   output formats may be selected.

[...]

makeinfo from the texinfo package

sudo apt install texinfo
makeinfo --html --no-split -o a.html a.texi
firefox a.html

You can also convert to many other formats if you prefer:

• makeinfo a.texi.

  Generates an a.info file which can be opened with:

  info -f a.info
  

  This is the most "native" local GNU documentation format.

• makeinfo --pdf a.info

  Requires LaTeX.

texi2html appears to have been deprecated in 2011: http://www.nongnu.org/texi2html/

development of Texi2HTML and of the Texi2HTML based makeinfo implementation stopped in 2011.

Tested on Ubuntu 20.04.

Binutils docs

Here is how you can build the Binutils docs like GDB and GAS, which are in texinfo format, to a single HTML page nirvana: https://unix.stackexchange.com/questions/477303/how-to-build-the-gdb-documentation-from-source/477309#477309

You can use texiinfo :

Texinfo uses a single source file to produce output in a number of formats, both online and printed (dvi, html, info, pdf, xml, etc.). This means that instead of writing different documents for online information and another for a printed manual, you need write only one document. And when the work is revised, you need revise only that one document. The Texinfo system is well-integrated with GNU Emacs.

You can downlod it from here, eg:

cd
wget http://ftp.gnu.org/gnu/texinfo/texinfo-6.0.tar.xz
tar xf texinfo-6.0.tar.xz

Compile and install:

cd texiinfo-6.0
./configure
make
sudo make install

After installation use man texiinfo and learn how to convert it .

More info Here