/usr/lib/x86_64-linux-gnu/ is in libauthen-sasl-cyrus-perl 0.13-server-10build5.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/perl5/
/usr/lib/x86_64-linux-gnu/perl5/5.26/
/usr/lib/x86_64-linux-gnu/perl5/5.26/Authen/
/usr/lib/x86_64-linux-gnu/perl5/5.26/Authen/SASL/
/usr/lib/x86_64-linux-gnu/perl5/5.26/Authen/SASL/Cyrus/
/usr/lib/x86_64-linux-gnu/perl5/5.26/Authen/SASL/Cyrus/Security.pm
/usr/lib/x86_64-linux-gnu/perl5/5.26/Authen/SASL/Cyrus.pm
/usr/lib/x86_64-linux-gnu/perl5/5.26/Authen/SASL/Cyrus.pod
/usr/lib/x86_64-linux-gnu/perl5/5.26/auto/
/usr/lib/x86_64-linux-gnu/perl5/5.26/auto/Authen/
/usr/lib/x86_64-linux-gnu/perl5/5.26/auto/Authen/SASL/
/usr/lib/x86_64-linux-gnu/perl5/5.26/auto/Authen/SASL/Cyrus/
/usr/lib/x86_64-linux-gnu/perl5/5.26/auto/Authen/SASL/Cyrus/Cyrus.so