\documentclass{article}
% Note: hyperref will signal error if hyperxmp's keywords are used, w/o loading hyperxmp!
% Note also that older hyperxmp has fewer new options!
\usepackage{hyperxmp}
\usepackage[draft,pdftitle={Test Hyperref Metadata},backref]{hyperref}
\title{Test Hyperref Metadata}
\author{A..~Author}
\hypersetup{
  pdfauthor={An Author},
  pdfkeywords={test,hyperref},
%  pdflang={English},
  pdfproducer={pdfLaTeX or LaTeXML},
  pdfsubject={Testing LaTeXML's processing of hyperref metadata},
}
\begin{document}
\maketitle
\section{Intentionally Left Blank}
Nothing left to say, really.
\hypersetup{
  pdfcopyright={Not subject to copyright},
  pdflicenseurl={http://creativecommons.org/licenses/by/3.0/},
}
\section{URL's}
Hyperref loads url, but redefines it
Special characters still neutralized:
 \url{http://example.com/foo_bar},
 \url{http://example.com/foo#bar},
 \url{http://example.com/foo&bar}.
\def\baz{index.html}
But macros expanded: \url{http://localhost/dir/\baz}.
And, you get this: \url{http://example.com/\~{}user}
\end{document}