/usr/lib/x86_64-linux-gnu/libmu_sieve.so.5 is in libmailutils5 1:3.4-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libmu_sieve.so.5.0.5
/usr/lib/x86_64-linux-gnu/libmu_sieve.so.5.0.5