\documentclass{article}
\usepackage{url}
\ifx\HCode\undefined
\usepackage{fontspec}
\setmainfont{Linux Libertine O}[Renderer = Harfbuzz]
\setmonofont{DejaVu Sans Mono}[Scale=MatchLowercase]
\fi
\usepackage{microtype,hyperref}
\usepackage[nodes]{uninormalize}
\usepackage{markdown}
\def\tightlist{}
\begin{document}
\title{The \texttt{uninormalize} package}
\author{Michal Hoftich\footnote{\url{michal.h21@gmail.com}} \and Arthur Reutenauer\footnote{\url{arthur.reutenauer@normalesup.org }}}
\date{Version 0.1\\28/12/2020}
\maketitle

\markdownInput[hybrid]{README.md}

\subsection{Example results}

\begin{itemize}
  \item combined letter ᾳ %GREEK SMALL LETTER ALPHA (U+03B1) + COMBINING GREEK YPOGEGRAMMENI (U+0345)
  \item normal letter ᾳ% GREEK SMALL LETTER ALPHA WITH YPOGEGRAMMENI (U+1FB3)
\end{itemize}

Some more combined and normal letters: 
óóōōöö

Linux Libertine does support some combined chars: \parbox{4em}{příliš}

Using the \verb|^^^^| syntax: ^^^^0061^^^^0301 ^^^^0041^^^^0301

\subsection{License}

Copyright: 2020 Michal Hoftich

This work may be distributed and/or modified under the conditions of the 
\textit{\LaTeX\ Project Public License}, either version 1.3 of this license or (at your option)
any later version. The latest version of this license is in
\url{http://www.latex-project.org/lppl.txt} and version 1.3 or later is part of all
distributions of \LaTeX\ version 2005/12/01 or later.

This work has the LPPL maintenance status \textit{maintained}.

The Current Maintainer of this work is Michal Hoftich.

\end{document}