/usr/share/perl5/Mail/Message/Head/ is in libmail-box-perl 2.110-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/perl5/Mail/Message/Head/Complete.pm
/usr/share/perl5/Mail/Message/Head/Complete.pod
/usr/share/perl5/Mail/Message/Head/Delayed.pm
/usr/share/perl5/Mail/Message/Head/Delayed.pod
/usr/share/perl5/Mail/Message/Head/FieldGroup.pm
/usr/share/perl5/Mail/Message/Head/FieldGroup.pod
/usr/share/perl5/Mail/Message/Head/ListGroup.pm
/usr/share/perl5/Mail/Message/Head/ListGroup.pod
/usr/share/perl5/Mail/Message/Head/Partial.pm
/usr/share/perl5/Mail/Message/Head/Partial.pod
/usr/share/perl5/Mail/Message/Head/ResentGroup.pm
/usr/share/perl5/Mail/Message/Head/ResentGroup.pod
/usr/share/perl5/Mail/Message/Head/SpamGroup.pm
/usr/share/perl5/Mail/Message/Head/SpamGroup.pod
/usr/share/perl5/Mail/Message/Head/Subset.pm
/usr/share/perl5/Mail/Message/Head/Subset.pod