/usr/share/doc/libscotchmetis-dev/CeCILL-C_V1-en.txt.gz is in libscotchmetis-dev 5.1.12b.dfsg-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libscotchmetis-dev/../libscotch-dev/CeCILL-C_V1-en.txt.gz