/usr/lib/scotch-int32/libptesmumps.so is in libptscotch-dev 5.1.12b.dfsg-2+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/scotch-int32/libptesmumps-5.1.so
/usr/lib/scotch-int32/libptesmumps-5.1.so