Trying to get that backslash

gistfile1.tex

\RequirePackage{filecontents}
\begin{filecontents*}{\jobname.bib}

@online{zotero-1855286-1414,
  title = {Faster \symbol{`\\} unfolding{} of communities: speeding up the Louvain algorithm},
  url = {http://www.patanalyse.com/sample-analysis.html}
}

\end{filecontents*}

\documentclass{article}
\usepackage[%
%  backend=bibtex   % use BibTeX
  backend=biber    % Use biber
]{biblatex}
\addbibresource{\jobname.bib}
\begin{document}

\symbol{`\\}

\nocite{*}

\printbibliography
\end{document}