/usr/share/doc/cadabra/reserved/indexbracket.tex is in cadabra 1.46-3.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 | \cdbreserved{indexbracket}{}
Denotes a group of objects with indices which are collectively
written, as in~\mbox{$(A + B + C)_{m n}$}.
The default properties of \verb|\indexbracket| are
\begin{verbatim}
\indexbracket{#}::Distributable.
\indexbracket{#}::IndexInherit.
\end{verbatim}
~
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