/usr/share/perl5/AtteanX/Serializer/ is in libattean-perl 0.017-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/perl5/AtteanX/Serializer/CanonicalNTriples.pm
/usr/share/perl5/AtteanX/Serializer/NQuads.pm
/usr/share/perl5/AtteanX/Serializer/NTriples.pm
/usr/share/perl5/AtteanX/Serializer/NTuples.pm
/usr/share/perl5/AtteanX/Serializer/RDFXML.pm
/usr/share/perl5/AtteanX/Serializer/SPARQL.pm
/usr/share/perl5/AtteanX/Serializer/SPARQLCSV.pm
/usr/share/perl5/AtteanX/Serializer/SPARQLHTML.pm
/usr/share/perl5/AtteanX/Serializer/SPARQLJSON.pm
/usr/share/perl5/AtteanX/Serializer/SPARQLTSV.pm
/usr/share/perl5/AtteanX/Serializer/SPARQLXML.pm
/usr/share/perl5/AtteanX/Serializer/Turtle.pm
/usr/share/perl5/AtteanX/Serializer/TurtleTokens.pm