/usr/share/lintian/overrides/masqmail is in masqmail 0.3.4-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | # has to be setuid:
masqmail: setuid-binary usr/sbin/masqmail 4755 root/root
|