%%
%% The LaTeX Companion, 3ed
%%
%% Example 9-6-25 on page I-726 in "Features not discussed in detail".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{135.0pt}

  %!TEX program = lualatex

  \setlength\parindent{0pt}

%StartShownPreambleCommands
\usepackage{fontspec}
%StopShownPreambleCommands

\begin{document}
\fontspec{Playfair Display}                -> <- <-> \hfill
\addfontfeature{Contextuals=AlternateOff}  -> <- <-> \par
\fontspec{Libertinus Serif}               SPQR Qu Qv \hfill
\addfontfeature{Contextuals=AlternateOff} SPQR Qu Qv
\end{document}