\ifx\CommitMarker\undefined
    \def\CommitMarker{unknown commit}
\fi

\iffinal
    % two-sided printing with chapters starting only at right pages
    \KOMAoptions{%
      …
    }
\else
    % single-sided printing for easier review and PDF viewing
    \KOMAoptions{%
    …
    % add hint which commit we are currently on
    \ifoot*{\CommitMarker}
\fi

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