pages.sty

% \titlepage, \partpage, \sectionpage, and \subsectionpage are defined in beamerinnertheme.sty

%%%%%%%%%%%% SPECIAL SECTIONS %%%%%%%%%%%%
\NewDocumentCommand{\extraslides}{+m}%
{%
    \iflatexpresents@handout%
    \else%
        % Insert the closing page, if requested
        \iflatexpresents@closingpage%
            % Set the boolean to false so that the closing page isn't added again by \end{document}
            \setboolean{latexpresents@closingpage}{false}
            % Insert the closing page
            \begin{frame}
                \closingpage{}
            \end{frame}
        \fi
        \appendix
        \part{Extra Slides}
        \begin{frame}
            \partpage{}
        \end{frame}
        #1
    \fi%
}%
%%%%%%%%%%%% END SPECIAL SECTIONS %%%%%%%%%%%%



%%%%%%%%%%%% SPECIAL PAGES %%%%%%%%%%%%
\newlength{\latexpresents@closing@origlogowidth}
\NewDocumentCommand{\closingpage}{}%
{%
    \settowidth{\latexpresents@closing@origlogowidth}{\latexpresents@titlelogos}%
    \multirowlayout[nodecorations, gutter=0pt]%
    {0.5}%
    {%
        \usebeamerfont{thanks}%
        \usebeamercolor{thanks}%
        \centering%
        \vfill%
        \strut\latexpresents@closing%
    }%
    [0.5]%
    [%
        \centering%
        \ifx\latexpresents@footlogos\@empty%
        \else%
            \vfill%
            \ifdim\latexpresents@closing@origlogowidth>0.5\elementwidth%
                \resizebox{0.5\elementwidth}{!}%
                {%
                    \usebeamercolor*{logo}%
                    \usebeamerfont*{logo}%
                    \latexpresents@footlogos{}%
                }%
            \else%
                \usebeamercolor*{logo}%
                \usebeamerfont*{logo}%
                \latexpresents@footlogos{}%
            \fi%
        \fi%
        \vfill%
        \strut\latexpresents@contact
    ]%
}%
%%%%%%%%%%%% END SPECIAL PAGES %%%%%%%%%%%%