\documentclass{article}

\usepackage[def=lmacs_tst]{lmacs}


\begin{document}

\section{Introduction}

The {\myCoolPkg} is designed to clean up the preamble of a source file.
For this file, we have
\begin{verbatim}
    \usepackage[def=lmacs_tst]{lmacs}
\end{verbatim}
The preamble definitions are in the file \texttt{lmacs\_tst.def}. For this
demo file, the only definition in \texttt{lmacs\_tst.def} in that of
\texttt{\string\myCoolPkg}. The \texttt{@} character has the catcode of
a letter, since the file is input via \texttt{\string\usepackage}.



\end{document}