\documentclass{article}
\usepackage{textcomp}
% RUN THIS WITH --includestyles
\message{Run LaTeXML with --includestyles}
\usepackage{whichpkga}
\usepackage{whichpkgb.sty}
% NOTE: Given only whichpkgc.sty
% THIS FAILS!!!
%\usepackage{whichpkgc.sty}
\begin{document}
\section{\TeX\ style input}
\paragraph{Given} whichfrag1, whichfrag1.tex and whichfrag1.tex.tex:
\verb|\input whichfrag1| \textrightarrow \input whichfrag1
\verb|\input whichfrag1.tex| \textrightarrow \input whichfrag1.tex
\paragraph{Given} whichfrag2 and whichfrag2.tex:
\verb|\input whichfrag2| \textrightarrow \input whichfrag2
\verb|\input whichfrag2.tex| \textrightarrow \input whichfrag2.tex
\paragraph{Given} whichfrag3:
\verb|\input whichfrag3| \textrightarrow \input whichfrag3
\section{\LaTeX\ style input}
\paragraph{Given} whichfrag1, whichfrag1.tex and whichfrag1.tex.tex:
\verb|\input{whichfrag1}| \textrightarrow \input{whichfrag1}
\verb|\input{whichfrag1.tex}| \input{whichfrag1.tex}
\paragraph{Given} whichfrag2 and whichfrag2.tex:
\verb|\input{whichfrag2}| \textrightarrow \input{whichfrag2}
\verb|\input{whichfrag2.tex}| \textrightarrow \input{whichfrag2.tex}
\paragraph{Given} whichfrag3:
\verb|\input{whichfrag3}| \textrightarrow \input whichfrag3
\section{usepackage}
\paragraph{Given} whichpkga and whichpkga.sty:
\verb|\usepackage{whichpkga}| \textrightarrow \whichpkga
\paragraph{Given} whichpkgb, whichpkgb.sty and whichpkgb.sty.sty:
\verb|\usepackage{whichpkgb.sty}| \textrightarrow \whichpkgb
% \paragraph{Given} whichpkgc.sty
% \verb|\usepackage{whichpkgc.sty}| \textrightarrow \whichpkgc
\end{document}