/usr/lib/libreoffice/share/template/bs/internal/idxexample.odt is in libreoffice-l10n-bs 1:3.5.2-2ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libreoffice/share/template/bs/internal/../../en-US/internal/idxexample.odt