Thanks Michal, you are a wizard. Committed to tex4ht + TL.

BTW, it's certainly not required, but thought I'd menion ... it would be an additional help if you could draft the ChangeLog entry to go along with patches.

This MWE fails when using $[B]$ in section title when the package titlesec is loaded

\documentclass[]{article}%
\usepackage{titlesec}
\begin{document}
\section{this is my $[B]$ section}
test
\end{document}

Error is

htlatex foo.tex

(/usr/local/texlive/2014/texmf-dist/tex/generic/tex4ht/html4.4ht)
(/usr/local/texlive/2014/texmf-dist/tex/generic/tex4ht/html4-math.4ht))
(./foo.aux)
! Extra }, or forgotten $.
<recently read> }

l.4 \section{this is my $[B]$ section}
?

When commenting the titlesec package, it compiles OK. Also, If I load the package, but change the title to $(B)$ instead of $[B]$ then it compiles OK as well. Only when using [] it is not happy.

The above MWE compiles OK with pdflatex and latex.

Version 3.14159265-2.6-1.40.15 (TeX Live 2014)

reference:

http://tex.stackexchange.com/questions/185866/why-package-titlesec-causes-tex4ht-to-give-error-when-using-in-section-titl/185892#185892